When electrons flow along the electron transport chains of mitochondria
a. the ph of the matrix increases
b. atp synthase pumps protons by active transport
c. the electrona gain free energy
d. nad is oxidized

a. the ph of the matrix increases

Explanation:

NADH and FADH2 molecules resulting from the Krebs cycle (by reducing respectively NAD + and Electron and proton carriers (e-  and H +), are oxidized in the final reactions of cellular respiration, and the electrons and protons are captured by oxygen, the final acceptor. The flow of electrons along the respiratory chain causes the active transport of protons along the chain through the inner membrane of the mitochondria. Protons return to the mitochondrial matrix by diffusion - chemiosmosis - and at the same time, ADP undergoes oxidative phosphorylation forming ATP. Because of this movement of protons inside the matrix, the ph of the matrix increases.

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.