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: Bivalves feed on plankton and nonliving organic matter., Fact2: Mussels are bivalve mollusks., Question: What feeds on plankton and nonliving organic matter? (A) barnacles (B) mollusks (C) animals (D) the Sun (E) sharks (F) graptolites (G) bacteria (H) dogs
B

Fact1: knowledge of the stars can be used to navigate, Fact2: Of course, astronomers also study stars., Question: What can be used to navigate? (A) music (B) backbones (C) astrology (D) cilia (E) magic (F) sponges (G) astronomy (H) lamphreys
G

Fact1: Temperature falls from the equator to the poles., Fact2: Temperature Temperature is an measurement of the amount of heat., Question: What falls from the equator to the poles? (A) heat (B) summer (C) water (D) Energy (E) warmth (F) cold (G) rain (H) ice

A