Q: Producers use energy and inorganic molecules for what?
Options:
- (A) neutralizing threats
- (B) dismissal of nutrients
- (C) heat produced
- (D) Transfers energy
- (E) retention of nutrients
- (F) decomposition
- (G) agriculture
- (H) iron in water
A: So, my chain of thought: Producers use energy and inorganic molecules to make food. Food preparation for retention of nutrients is included. Producers use energy and inorganic molecules for the retention of nutrients. The answer is (E).

Q: Cells do not include
Options:
- (A) harmful substances
- (B) sulfate particles
- (C) the smallest agent of disease
- (D) direct damage to the lungs
- (E) sub-units of species
- (F) Inches or fractions of inches.
- (G) Something with a head, thorax, and abdomen
- (H) Direct sunlight.
A: So, my chain of thought: Viruses are not cells. Viruses Viruses are the smallest agents of disease. The smallest agents of disease are not cells. The answer is (C).

Q: What is a natural part of aging?
Options:
- (A) Smoking
- (B) apoptosis
- (C) regeneration
- (D) illness
- (E) stimulation
- (F) cracking
- (G) Weight
- (H) firm skin
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
So, my chain of thought: Aging is associated with the death of cells. Apoptosis means cell death. Apoptosis is a natural part of aging. The answer is (B).