Q: When a stream flows from a hard to soft rock area, what is often formed? Choices: - a lake - a river - a riverbank - a waterfall A:
a waterfall

Q: What happens if a molecule forms strong bonds to the catalyst? Choices: - molecules gets poisoned - surface gets poisoned - membrane gets poisoned - catalyst gets poisoned A:
catalyst gets poisoned

Q: What is considered the center of the solar system? Choices: - nebulla - earth - heat - sun A:
sun

Q: When warm air rises up to the tropopause, where does it flow? Choices: - east or north - west or south - east or west - north or south A:
north or south