In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Fact1: Antigens are molecules that the immune system recognizes as foreign to the body., Fact2: Children are born with an immature immune, or defense, system., Question: What are molecules that the defense system recognizes as foreign to the body? (A) Allergies (B) lungs (C) antigens (D) bacteria (E) parasites (F) atoms (G) red blood cells (H) acetic acid
C

Fact1: Temperature falls from lower to higher altitudes., Fact2: If the weather is warm, their temperature rises., Question: What falls from lower to higher altitudes? (A) warm weather (B) sun's heat (C) rainfall (D) heat energy (E) kinetic energy (F) water vapor (G) colder and wetter (H) Greenhouse gasses
A

Fact1: Behaviors that improve fitness increase through natural selection., Fact2: Adaptation is the result of natural selection., Question: Behaviors that improve fitness increase through what? (A) kinetic energy (B) Animal survival (C) increases (D) hydration (E) Riding a bike (F) competition (G) adaptation (H) insulation

G