The movement of molecules from an area of higher concentration to an area of lower concentration is called:

Correct Answer: D

Rationale: Simple diffusion moves molecules down their concentration gradient.

Correct Answer: A

Rationale: Simple squamous epithelium, with its thin, flat cells, lines the lungs and blood vessels for efficient gas exchange.

Correct Answer: A

Rationale: Group A individuals have anti-B antibodies; genotype must be AA or AO, not AB; they can have an O parent (AO offspring) and children of A or O.

Correct Answer: A

Rationale: Blood is ~7-8% of body weight; it's a lower percentage in obese individuals due to higher fat mass.

Correct Answer: C

Rationale: Inulin measures ECF volume as it's confined to extracellular spaces; D2O measures TBW, not ICF directly.