input with options: Q: What are negative electrons attracted to? A:
OPTIONS:
- hormones
- ions
- neutral electrons
- positive protons
output: positive protons

Q: Q: All of the living things in an area and the nonliving environment together make up what? A:

OPTIONS:
- biosphere
- biome
- taiga
- ecosystem

A: ecosystem

input: OPTIONS:
- amino acids
- carotenoids
- hydrocarbon chains
- nucleotides Now, answer this question: Q: Phosphate groups are found within phospholipids and what else? A:
A:
output: nucleotides

Q: What type of tissues are major barriers to the entry of pathogens into the body? A:

OPTIONS:
- skin
- vascular
- nasal
- mucosal

Answer: mucosal

Problem: OPTIONS:
- carbon
- solid
- atoms
- vapor
Q: Q: When a supercooled liquid boils, the temperature drops as the liquid is converted to what? A:
Answer: vapor

Q: How many classes of biochemical compounds are there? A:

OPTIONS:
- one
- five
- three
- four

Answer:
four