*Question*
Q: When does sublimation occur? Choices: - when the wind changes direction - when the snow melts the ice caps - when the ice and sand change directly into water vapors - when the ice and snow change directly into water vapors A:
**Answer**
when the ice and snow change directly into water vapors

*Question*
Q: Cephalochordates have a notochord and nerve cord but not a? Choices: - digestive system - nervous system - brain - backbone A:
**Answer**
backbone

*Question*
Q: Crystallization separates mixtures based on differences in what, which usually increases with temperature? Choices: - density - viscosity - humidity - solubility A:
**Answer**
solubility

*Question*
Q: Secondary consumers are usually carnivores that eat what? Choices: - soil - plants - dead material - primary consumers A:
**Answer**
primary consumers