*Question*
Q: The products of photosynthesis are glucose and what else? Choices: - carbon - hydrogen - nitrogen - oxygen A:
**Answer**
oxygen

*Question*
Q: What organ breaks down excess amino acids and toxins in the blood? Choices: - kidney - heart - lungs - liver A:
**Answer**
liver

*Question*
Q: Every species has a characteristic number of what? Choices: - ribosomes - receptors - DNA - chromosomes A:
**Answer**
chromosomes

*Question*
Q: What do you call the system of glands that release chemical messenger molecules into the bloodstream? Choices: - homeostasis system - nervous system - limbic system - endocrine system A:
**Answer**
endocrine system