Final answer:
Infants are at higher risk for drug toxicity primarily due to decreased liver enzymes and reduced kidney perfusion, as their immature organ systems cannot efficiently metabolize and eliminate drugs.
Step-by-step explanation:
Infants are at risk for drug toxicity due to several factors. The ones that apply to this question are decreased liver enzymes and reduced kidney perfusion. Infants have immature liver and kidney functions, which makes them less efficient at metabolizing and eliminating drugs. This inefficiency is due to lower enzyme activity in the liver, which is necessary to break down drugs, and decreased function in the kidneys, which are responsible for filtering waste from the blood and excreting it. Both organs are crucial for removing potentially toxic substances from the body, and their underdevelopment in infants puts them at a higher risk for toxicity.