Answer:
The correct answer is option B) "stabilizing selection".
Explanation:
Stabilizing selection is a type of natural selection at which mean traits are favored by nature instead of extreme values. In this case at which sparrows with average-sized wings survive severe storms better than those with longer or shorter wings illustrates stabilizing selection. It its believed that this type of selection is the most commonly found in nature, since most traits have no extreme values in most of the species.
I'm not sure, but I think it would be mud.
Answer:
The order must be K2→K1, since the permanently active K1 allele (K1a) is able to propagate the signal onward even when its upstream activator K2 is inactive (K2i). The reverse order would have resulted in a failure to signal (K1a→K2i), since the permanently active K1a kinase would be attempting to activate a dead K2i kinase.
Explanation:
- You characterize a double mutant cell that contains K2 with type I mutation and K1 with type II
mutation.
- You observe that the response is seen even when no extracellular signal is provided.
- In the normal pathway, i f K1 activat es K2, we expect t his combinat ion of two m utants to show no response with or without ext racell ular signal. This is because no matt er how active K1 i s, it would be unable to act ivate a mutant K2 that i s an activit y defi cient. If we reverse the order, K2 activating K1, the above observati on is valid. Therefore, in the normal signaling pathway, K2 activates K1.
