Im a bit confused, so if anyone could me, that would be great!
what are nadh and fadh2 used for in cellular respiration?

NADH and FADH2 act as reducing equivalent that means these two compounds donate electron to other molecule such as oxygen to reduce later into water by oxidizing themselves.

Explanation:

NADH and FADH2 are the reduced form of NAD+ and FAD which are used as co enzymes.

                 NADH and FADH2 are formed during glycolysis and TCA cycle.These 2 reducing equivalent enters Electron transport Chain and donate electrons, these donated electrons are then transported through various electron carriers to final electron acceptor oxygen thus reducing oxygen to water and also regenerate their original form respectively called  NAD+ and FAD.

what have scientists found to be the most efficient and effective way to insert new sequences into an individual? a-scientists have created genetically altered foods that release dna during digestion. b-scientists use viruses to insert specific gene sequences. c-scientists irradiate genes so that they can be absorbed through the skin.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.