*Question*
Q: The average number of individuals per unit of area can be expressed as what? Choices: - the percent of population - percent density - total density - population density A:
**Answer**
population density

*Question*
Q: All atoms have equal numbers of what two particles? Choices: - nuclei and neutrons - photons and protons - electrons and neutrons - electrons and protons A:
**Answer**
electrons and protons

*Question*
Q: A current in a circuit needs a complete what? Choices: - cause - speed - stream - path A:
**Answer**
path

*Question*
Q: What do most amphibians breathe with as larvae? Choices: - pores - lungs - nasal passages - gills A:
**Answer**
gills