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: Air pollution harms the respiratory and circulatory systems., Fact2: Cars are a significant source of air pollution., Question: What harms the respiratory and circulatory systems? (A) oil (B) rain (C) sulfur (D) cars (E) tires (F) coal (G) tar (H) bicycles
D

Fact1: Steroid hormones are made of lipids, such as phospholipids and cholesterol., Fact2: Fats are known as lipids., Question: What are steroid hormones made of? (A) bacteria (B) fats (C) sugar (D) muscle (E) H 2 O (F) sunlight (G) the Sun (H) SO2
B

Fact1: Evolution is a change in the characteristics of living things over time., Fact2: Evolution is the study of living things with time., Question: What does evolution study over time? (A) Plant reproduction (B) sensory neurons (C) Plants growth (D) Animal survival (E) survival (F) competition (G) characteristics (H) light energy
G