instruction:
You are given a science question (hard-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:
For many years, scientists have found fossils in rock layers in all parts of the world. Eventually scientists discovered that many of the rock layers showed the same pattern of older fossils being located in deeper rock layers and younger fossils being located in shallower layers. This discovery is an example of how scientific knowledge changes as
(A) fossils are preserved in different ways. (B) conclusions about fossils are revised into questions. (C) fossils are formed in different areas. (D) new fossil evidence is reviewed.
answer:
D

question:
Sooj learned that whales use vocalization to navigate and to communicate with other whales. Some scientists think that noise pollution in whale habitats may harm whale populations. What would be the most likely effect of noise pollution on whales?
(A) alteration of whale genetic material (B) reversed flow of energy through whale habitats (C) reduced populations of food organisms in whale habitats (D) separation of whale family groups
answer:
D

question:
Which question can be answered through scientific investigation?
(A) How does solar energy affect cloud formation? (B) Why are tigers more beautiful than iguanas? (C) What is the best subject to study at college? (D) Should humans invest in space travel?
answer:
A