Q: If deep valleys are formed by flowing rivers through erosion over long periods of time, then what are formed by flowing rivers through erosion over long periods of time? Answer choices: - deserts - a hydraulic system - deep valleys - pyramids - Calcium carbonate - patch reefs - buildings - Sediment
A: deep valleys

Q: If floods cause landslides, then what can cause a landslide? Answer choices: - tornado - rivers - lightning - flood - cracks - storm - wind - rocks
A: flood

Q: If androgens are chemical messengers, then androgens and what kind of messengers? Answer choices: - animals - interact - organ - humans - chemical - PDAs - allow growth - kinetic
A: chemical

Q: If the number of rings in a tree trunk can be used to estimate how many years old it is, then what unit of time can be estimated by the rings in a tree trunk? Answer choices: - hours - decades - months - H20 - Joules - DNA - years - seasons
A: years