The structure of an atom is best described as:   1.  neutrons in orbit about a nucleus of protons bound to electrons.2. electrons and neutrons in orbit about a nucleus of protons  3. protons and neutrons in orbit about a nucleus of electrons  .4. electrons in orbit about a nucleus of protons and neutrons

Option (4) is the correct answer.

Explanation:

An atom consists of three types of sub-atomic particles which are electrons, protons, and neutrons.

Protons have a positive charge and neutrons have no charge. Whereas electrons have a negative charge.

Protons and neutrons are placed inside the nucleus of an atom. On the other hand, electrons revolve around the nucleus of the atom.

Thus, we can conclude that the structure of an atom is best described as electrons in orbit about a nucleus of protons and neutrons.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.

"do a testcross with a homozygous recessive plant."