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: erosion causes a river to become deeper and wider, Fact2: Weathering and erosion continue to shape it today., Question: Weathering causes what to become deeper and wider? (A) a landslide (B) Sediment (C) a mountain (D) a volcano (E) soils (F) rock (G) flooding (H) a river
H

Fact1: a planet rotating causes cycles of day and night on that planet, Fact2: Our bodies and senses adjust to the cycle of day and night so that we may work in the day and sleep at night., Question: Sleeping at night and working during the day is determined by what thing happening? (A) clouds forming (B) planet rotating (C) heat energy (D) dehydration (E) solar flares (F) animal reproduction (G) Animal survival (H) sweating

B