Which statement about the respiratory electron transport chain is true?
a. electrons are received from nadh only.
b. the terminal electron acceptor is usually h2o.
c. most of the respiratory proteins are in the cytosol.
d. energy must be added to move electrons from one electron carrier to the next.
e. electrons are passed from donor to recipient carrier molecules in a series of oxidation–reduction reactions.

Explanation:

Letter A is false, because electrons are received from NADH and FADH2

Letter B is false, because the terminal electron acceptor is usually O2

Letter C is false, because most of the enzymes are part of the inner mitochondrial membrane.

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.