*Question*
Q: Acting like drawstrings to close off the alimentary canal, what regulates the passage of material between compartments? Choices: - intestine - hamstring - uterus - sphincter A:
**Answer**
sphincter

*Question*
Q: What is an insect's hard outer exoskeleton made out of? Choices: - lectin - casein - melanin - chitin A:
**Answer**
chitin

*Question*
Q: Original atoms are called what type of isotopes? Choices: - offspring - component - product - parent A:
**Answer**
parent

*Question*
Q: What do most ecosystems get energy from? Choices: - magma - moisture - evaporation - sunlight A:
**Answer**
sunlight