input: OPTIONS:
- chewing tobacco
- heredity
- tuberculosis
- tobacco smoke Now, answer this question: Q: What is the leading cause of lung cancer? A:
A:
output: tobacco smoke

Q: What is a primary source of the hormone melatonin? A:

OPTIONS:
- thymus
- pituitary gland
- thyroid gland
- pineal gland

Answer: pineal gland

Problem: OPTIONS:
- methane
- carbon dioxide
- nitrogen
- oxygen
Q: Q: What does hemoglobin in blood carry to the cells? A:
Answer: oxygen

Problem:OPTIONS:
- habitat
- population
- biodiversity
- ecosystem

Q: The community of all of the living and nonliving parts of an environment is known as what? A:
****
A: ecosystem

Q: Changes of state of matter do not involve what type of reaction? A:
OPTIONS:
- gaseous reaction
- radiation
- mechanical reaction
- chemical reaction
chemical reaction

Q: What is the limiting factor for bacteria in a dish? A:
OPTIONS:
- density
- speed
- material
- space

Answer:
space