instruction:
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.
question:
Estuaries are marine environments located in areas where fresh water from rivers flow into the ocean. Estuaries are one of the most biologically productive ecosystems. Birds, fish, turtles and many other organisms inhabit these ecosystems. Which will most likely cause changes to estuary habitats on a global scale?
(A) decreases in powerful hurricanes (B) decreases in volcanic eruptions (C) increases in earthquakes (D) increases in sea level
answer:
D

question:
What is the primary function of white blood cells in humans?
(A) carry oxygen (B) fight disease (C) grow tissues (D) remove waste
answer:
B

question:
There are several different types of rock. Each type of rock is formed under different conditions. How are sedimentary rocks, such as shale and sandstone, formed?
(A) Particles are heated by the Sun. (B) Particles are melted together by magma. (C) Particles are compressed into layers. (D) Particles are changed into liquids.
answer:
C