Pharmaceutical Chemistry: Pharmacokinetic and Biopharmaceutical Aspects of Drug Molecules

Which of the following best describes the term 'bioavailability' in pharmacokinetics?

Which pharmacokinetic parameter is directly affected by the volume of distribution ($V$) in the equation below? $C(t) = \frac{F \times D}{V} \times \frac{k_a}{(k - k_a)} \times \left( e^{-\frac{CL}{V} \times t} - e^{-k_a \times t} \right)$

A drug is administered orally and must pass through the gastrointestinal tract before entering the bloodstream. Which of the following is NOT a physiologic factor that affects its absorption?