Answer: The second factor that leads to fluidity is the nature of the phospholipids themselves. In their saturated form, the fatty acids in phospholipid tails are saturated with bound hydrogen atoms; there are no double bonds between adjacent carbon atoms. This results in tails that are relatively straight
Answer:
External means on the outside, so it can be something like their fur color. Some other features can be number of legs, if they have wings or not, etc.
B because they are made from the exact material
I believe the answer is b. gene flow
