Answer:
C. tetanic contractions might occur, which would stop the heart's pumping action.
Explanation:
The absolute refractory period of the cardiac muscle action potential refers to the time interval when the voltage gated sodium channels are inactivated. The absolute refractory period lasts ~180 msec. The action potential lasts 200-220 msec.
The refractory period of cardiac muscle is dramatically longer than that of skeletal muscle. This prevents tetanus from occurring and ensures that each contraction is followed by enough time to allow the heart chamber to refill with blood before the next contraction.
In order words, It is important for the cardiac muscle cells to have a longer refractory period, because if they were short like the skeletal muscles, the heart could enter tetanic contraction/summation which is when muscle is stimulated so rapidly that it does not have a chance to relax at all between stimuli.
<h2>Previously understood similarities that seemed to connect slime molds and fungi are now considered to be examples of convergent evolution</h2>
Explanation:
- Convergent evolution is an evolutionary process where unrelated monophyletic organisms independently develop or evolve similar characteristic traits due to the need to adapting to similar conditions or ecological or environmental necessity.
- The slime molds are subsets or part of amoebozoans but have certain morphological features similar to that of fungi, this type of evolutionary behavior is called convergent evolution.
- Under stressful conditions, slime molds produce and develop spore-generating fruity bodies like fungi, which is a convergent evolutionary change.
Answer:E. Down-regulation
Explanation:Cells typically up or down regulate depending on the concentration of a hormone levels. When there is a excessive concentration of a hormone in the blood stream, the cell decreases the number of receptors reducing the interaction with that hormone, Also, when there is excessive hormone reduction, the target cells activate to increase their number of receptors.
Down regulation occurs by the the deactivating or degrading of target cells to reduce the number of receptors due to their sensitivity to a particular excess hormone.
The kinetic energy is 375 (I don’t know the units)
