Answer:
Daphnia is an ideal system for studying multiple stressors because of its short generation time, well-studied ecology and evolutionary history, wide geographical distribution across many limnetic systems, high mutation and recombination rates, high sensitivity to changes in environmental conditions, unique cyclical
Explanation:
All medical research is carefully planned, and this includes medical
research with animals. Experts who review a scientist’s proposed
experiment involving animals weigh several considerations before
approving each study.
The most important thing is that the research must be relevant
to human or animal health. Studies need to protect the animals’
welfare. That means that only the fewest number of the most
appropriate species may be used. Under federal law, all animals
must be treated humanely and undergo the least distress possible
Answer:
Famine.
Explanation:
Famine, a shortage of water or food, will often result in a significant population decrease.
Answer:
Sub-threshold
Explanation:
If the stimulus is too small to generate the action potential, it is considered as subthreshold stimulus. Subthreshold stimulus causes the opening of small number of sodium channel i.e. not enough to generate action potential because action potential is generated by complete reversal of membrane polarity. Slight depolarization is caused by subthreshold stimulus by the opening of inadequate number of sodium channel but its magnitude is not enough to reach the threshold voltage. Consequently the action potential is not generated.
The response produced by subthreshold stimulus is called as local response or local depolarization because it could not travel further. The minimum stimulus required to generate the action potential is call as threshold stimulus and stimulus greater than threshold stimulus is called as suprathreshold stimulus. It changes the frequency of generated action potential.
The Chondrichthyes are the cartilaginous fishes including the sharks, rays,<span>skates and chimeras. The Osteichthyes are the bony fish. Both of these groups </span>became established during the Devonian Period about 400 million years ago. The Chondrichthyes <span>differ from the Osteichthyes in many respects, including their</span><span>
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