Explanation:
The Precambrian covers almost 90% of the entire history of the Earth. It has been divided into three eras: the Hadean, the Archean and the Proterozoic. The Precambrian Era comprises all of geologic time prior to 600 million years ago.
Arrange these muscle contraction events in the correct order.
1. nerve stimulus
2. myosin attaches to actin causing a twitch
3. acetylcholine binds to receptor
4. calcium channels open
5. sarcoplasmic reticulum releases calcium
6. impulse rides along sarcolemma
7. exocytosis occurs releasing acetylcholine into synaptic cleft
8. calcium binds to troponin moving tropomyosin out of the way
9. impulse enters the cells via the t-tubule
10. acetylcholine vesicles move to endplate
Answer:
1. nerve stimulus
4. calcium channels open
10. acetylcholine vesicles move to endplate
7. exocytosis occurs releasing acetylcholine into synaptic cleft
3. acetylcholine binds to receptor
6. impulse rides along sarcolemma
9. impulse enters the cells via the t-tubule
5. sarcoplasmic reticulum releases calcium
8. calcium binds to troponin moving tropomyosin out of the way
2. myosin attaches to actin causing a twitch
Explanation:
The central nervous system generates an action potential (1) that travels to the muscle fiber activating the calcium channels (4). Calcium triggers vesicles fusion to the presynaptic membrane (10) releasing acetylcholine (Ach) into the synaptic space (7). Once there, Ach binds to its receptors (3) on the postsynaptic membrane of the skeletal muscle fiber, causing ion channels to open. Positively charged sodium ions cross the membrane to get into the muscle fiber (sarcoplasm) and potassium leaves the cell. The difference in charges caused by these ions transport charges positively the muscle fiber membrane (6). It depolarizes. The action potential enters the t-tubules (9) depolarizing the inner portion of the muscle fiber.
Contraction initiates when the action potential depolarizes the inner portion of the muscle fiber. Calcium channels activate in the T tubules membrane, releasing calcium into the sarcolemma (5). At this point, the muscle is at rest, and the tropomyosin is inhibiting the attraction strengths between myosin and actin filaments. Tropomyosin is obstructing binding sites for myosin on the thin filament. When calcium binds to troponin C, troponin T alters the tropomyosin position by moving it and unblocking the binding sites (8). Myosin heads join to the uncovered actin-binding points forming cross-bridges (2), and while doing so, ATP turns into ADP and inorganic phosphate, which is released. Myofilaments slide impulsed by chemical energy collected in myosin heads, producing a power stroke. The power stroke initiates when the myosin cross-bridge binds to actin (2). As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Finally, Z-bands are pulled toward each other, shortening the sarcomere and the I-band, producing muscle fiber contraction.
Smallholders have historically been for-profit commercial horticulturalists rather than subsistence farmers.
True
False
Answer:
true
Explanation:
1.What are the three different patterns of leaf attachment?
2. What is the purpose of a plants stem?
3.What are the differences in the kinds of stems?
4. What are the parts of stems?
5.What are roots and what are the functions of roots?
Answer:
1) alternate, opposite and whorled
2) the primary functions Of the stem are to support the leafs to conduct water and minerals to leafs, where they can be converted into usable products by photosynthesis
3) stesms stores food, water, and nutrients. cells of steam , meristems, produce new living tissues. underground stem, aerial stem and subaerial steam are three different stem
4) the are six elements 1 nodes 2 internodes 3 terminal or apical bud 4 lateral or axillary bud 5 petiole 6 pedecel. while the two organd are 7 leaves and 8 flowers
5) roots = in botany that parts of vascular plant normally underground FUNCTIONS are anchorage of plant absorption of water and dissolved minerals and conditions of these to stem, and storage of reserve foods
Explanation:
well that took longer than expected
Which of the following statement is correct about about the hierarchy of the taxonomic system currently used to classify organisms
A. Many different classes of organisms belong to the same order
B. All organisms of given phylum belong to the same kingdom
C.Many different families of organisms belong to the same Genus
D. All organisms and given order belong to the same species
Answer:
A
Explanation:
Took the test
The statement 'all organisms of given phylum belong to the same kingdom' is correct about the hierarchy of the taxonomic system (Option B).
In the classification system, the Phylum is a division within the Kingdom.It means that all organisms that form a Phylum are found in the same Kingdom.The current system of biological classification is based on evolutionary and taxonomic features.In conclusion, the statement 'all organisms of given phylum belong to the same kingdom' is correct about the hierarchy of the taxonomic system (Option B).
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A woman with blood type a (whose parents both had AB blood) mates with a man with blood type B (his mother was AB and the father was O blood). Show the cross and the genotype and phenotype ratios of the potential offspring.
Answer:
1 AB:1 A
Explanation:
Ia Ia
Ib IaIb IaIb
i Iai Iai
i represents type O blood which is always recessive
the capital I represents co-dominant traits (a or b)
Iai is type A because O is recessive and will be masked by Ia
IaIb is type AB because both capital I traits will be codominant
This cross ultimately gives a 1:1 ratio of type A to type AB
The more diverse an ecosystem is - *
5 points
A) The more threatened its population are
B)The more similar the species will be
C)The more healthy and stable it is
D)The fewer varieties of species are present
Answer: C
Explanation: I took the test hoped this helped :)
The most abundant element in earths continental crust by weight is
The most abundant element in earths continental crust by weight is oxygen.
plsssssss help
NO LINKS pls
5. The ____
controls the rate of breathing.
Answer: respiratory control centers
Explanation: respiratory control centers: The medulla which sends signals to the muscles involved in breathing, and the pons which controls the rate of breathing.The medulla oblongata is the primary respiratory control center. Its main function is to send signals to the muscles that control respiration to cause breathing to occur.
Answer:
medulla oblongata
Explanation:
its a part of the raspatory response in your brain
i hope this helps :3
My teacher's notes are jumbled so I can't really answer these properly
Answer:
search up a diagram of an eye simplified
Explanation:
it worked for me
(a) Describe a method to measure the mean number of weeds per m’in each field.
Answer:
Describes the role of monitoring in adaptive management. ... each vegetation attribute and advice on field techniques and tools are provided. ... If you are using sampling to estimate population sizes or mean values (such as density, ... obtain the true average number of plants per quadrat (4 plants/quadrat).
Explanation:
Quadrat method is the most widely used method for population determination in plants and small immobile organisms.
What are the methods for population determination?The Quadrat method is the most useful method for population determination for immobile organisms such as plants or for very small and slow-moving organisms. The plots used in this method is called quadrats, which may be used to determine the population size and density of a population. Here, each quadrat marks off an area of the same size which is typically, a square area or other shape such as circular or other within the given habitat.
The most accurate way to estimate the weed population is to count the number of plants in an area of known size at a different number of locations. Through the use of a quadrant, which may be square or circular in shape weed plant counts can be carried out.
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What is a body fossil according to the video?
Answer:
Body fossils are the remains of the body parts of ancient animals, plants, and other life forms.
Explanation:
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What is friction А a force that slows an object down B a force that speeds an object up ca force that makes an object start moving Da force that can move very heavy objects
Answer:
.V.JHRM.TLNGOYIG
Explanation:
Answer:yo am cool lol
Explanation:
PLZ HELP I AM TAKING A QUIZ!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Are involuntary muscles
A) cardiac
B) smooth
C) skeletal
Answer:
QUESTION:
Are involuntary muscles
A) cardiac
B) smooth
C) skeletal
ANSWER:
muscle governing reflex functions and not under direct voluntary control especially: smooth muscle.
Explanation:
Hope that this helps you out! :)
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Have a great rest of your day/night!
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plssssss help
No links
Answer:
1. Net force
2. Newton
3. Balenced
4. Un Balenced
Correct me if im wrong
Try This one out no links on My question or I will report you
the 10% rule of ecosystems says that only 10% of the energy is passed in to the next trophic level. what happens to the rest of the energy?
A- it goes back into plants
B- we dont know what happens to it
C- it gets released into the environment as heat
It is not enough to be in the presence of a pathogen like a bacteria or virus, there also needs to be an environment in which the pathogen can grow.
a. True
b. False
Organisms produced as a result of mitosis exhibit a great deal of genetic variation.
Answer:
false
Explanation:
Which factor correlated with human populations losing skin pigmentation? (1 point)
O moving away from the poles
moving away from mountainous environments
moving away from shaded environments
moving away from the equator
Explanation:
moving away from shaded environment
The main factor correlated with human populations losing skin pigmentation is moving away from the equator.
What is melanin?Melanin is a specific protein associated with skin pigmentation in humans and mammals in general.
In humans, melanin levels are related to the amount of solar radiation, which is a consequence of latitude.In regions of low latitude, melanin levels are higher than in high latitude regions.In conclusion, the main factor correlated with human populations losing skin pigmentation is moving away from the equator.
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Fill in the blanks on the table with the names of the atmospheric layers, their chemical
compositions, temperature trends, and aircraft needed for travel. (10 points)
Answer:
Hope this helps
The atmosphere of Earth is composed of five different layers namely exosphere, thermosphere, mesosphere, stratosphere and troposphere.
Different layers of the atmosphere have various functions are located at different temperature and pressure regions.
The correct answers for the blanks are attached in the image below:
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I need help on this plzzzzz
Answer:
c. X: commensalism
Y: Parasitism
Z: Mutualism
Explanation:
X: commensalism
Rationale: in this type of relationship, only one organism benefits while the other does not benefit and is also not harmed in anyway. Whale doesn't benefits and it's not harmed by the Barnacles that benefits from the association.
Y: Parasitism
Rationale: in parasitism, one organism suffers while the other benefits in the relationship.
The fleas on warm-blooded animals is the organism that benefits solely from the association while the animals suffer.
Z: Mutualism
Rationale: in this relationship, both organisms benefit from the association and do not harm each other.
The Fungal and plant roots benefit each other.
A bottle of concentrated 20 M ammonia solution needs to be diluted to
1 M strength for laboratory use. In order to make up 1 L of 1 M
ammonia solution, how much concentrated ammonia must be diluted?
Answer:
The aim of question is to know about molarity of ammonia solution 25% . ... If you have 17 g NH3 in 1000 ml H2O, you have a 1M NH3. ... Can you not titrate it using standardised acid? ... Mass concentration of ammonia in stock solution = ... So 1 M means 35.04gr in a liter of water and because the solution ...
9 answers
·
Top answer:
The ammonia solution (NH3) of 25% means 25 gr NH3 in 100 ml water.
Explanation:
most of a cell's life is spent in carrying out its specific tasks
Answer:
INTERPHASE
Explanation:
27. How many senators does each state have?*
3
1
4
2
Government
Answer:
2
Explanation:
Answer:
2
Explanation:
Why might scientists have additional questions to answer at the end of an
investigation?
The condition of Earth’s atmosphere at a particular time and place is called _________________.
Explanation:
The condition of earths atmosphere at a particular time and place is called weather
True or False?
Relative risk is an ideal form of measurement for a retrospective cohort study design because it allows researchers to recruit both individuals with the outcome of interest and individuals without the outcome of interest, then match individuals from each of the respective groups to individuals of the other group to determine if a specific exposure caused the outcome of interest.
Answer:
False
Explanation:
Goold luck and have a great day c:
A cell from a tissue culture has 38 chromoses after mitosis and cytokinesis one daughter cell has 37 what might occurred to cause the abnormal chromosome number
Answer:
occurred an aneuploidy (monosomy)
Explanation:
Aneuploidy can be defined as a chromosomal aberration in which the chromosome number is abnormal. In an aneuploidy, the number of total chromosomes in daughter cells is not an exact multiple of a haploid set, by either gaining or losing chromosomes during mitosis. Aneuploidies are common in cancer cells and in different types of chromosome disorders. Moreover, monosomy is a type of aneuploidy in which daughter cells have a single chromosome copy instead of the two copies found in diploid cells. For example, Turner syndrome is a monosomy caused by the loss of the X chromosome.
The reactions of lactate fermentation in muscle cells happen in the
Answer:
Lactic acid fermentation
Explanation:
