You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Which two body systems maintain the level of glucose in the blood?  
 (A) nervous and respiratory systems (B) digestive and endocrine systems (C) muscular and immune systems (D) skeletal and cardiac systems
B

Some pea plants always have peas with smooth skin. Other pea plants always have peas with wrinkled skin. How can a student best predict which kind of pea will grow from a seed that is planted?  
 (A) by checking the amount of water in the soil (B) by checking how often the pea plant receives sunlight (C) by checking how much space the plant will have to grow (D) by checking the type of peas growing on the parent plants
D

The first person to introduce the idea of the continents moving around the surface of Earth was  
 (A) Niels Bohr. (B) Albert Einstein. (C) Charles Darwin. (D) Alfred Wegener.

D