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").

[EX Q]: Fact1: All chemical reactions require activation energy to get started., Fact2: Chemical changes are a result of chemical reactions., Question: What is required before a chemical change? (A) kinetic energy (B) energy usage (C) activation push (D) activation energy (E) activation switch (F) activation power (G) Burning fuel and air (H) Evaporation
[EX A]: D

[EX Q]: Fact1: Balance is the ability to sense and maintain body position., Fact2: People fall when they lose their sense of balance., Question: the ability to sense and maintain body position prevents people what (A) falling (B) death (C) illness (D) starving (E) blindness (F) disease (G) depression (H) sweating
[EX A]: A

[EX Q]: Fact1: gravity causes objects that have mass to be pulled down on a planet, Fact2: Another name for Mars is the Red Planet., Question: Gravity causes what to be pulled down on Mars? (A) space (B) living things (C) hydrogen and oxygen (D) massless objects (E) objects that have mass (F) fissures of hot, acidic water (G) nothingness (H) principals of aerodynamics
[EX A]:
E