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.

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.