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:
The excessive use of nitrogen-based fertilizers causes runoff that increases the nitrogen content of lakes and bays. These nitrogen compounds directly affect the aquatic ecosystems by  
 (A) interfering with the water cycle. (B) decreasing the predator population. (C) increasing the rate of algae growth. (D) causing aquatic animals to grow larger.
answer:
C


question:
Amylase is a chemical that decomposes starch into maltose and dextrin. Which best describes the role of amylase in the human body?  
 (A) as an inhibitor of insulin production (B) as an enzyme that aids in digestion (C) as a catalyst for protein synthesis (D) as a receptor of fatty acid chains
answer:
B


question:
A person produces two sound waves with a flute, one immediately after the other. Both sound waves have the same pitch, but the second one is louder. Which of the following properties is greater for the second sound wave?  
 (A) Frequency (B) Amplitude (C) Wavelength (D) Speed in air
answer:

B