Q: What builds up in an artery and reduces blood flow? Choices: - pressure - calcium deposits - surface tension - plaque A:
plaque

Q: What are the "chemical messenger" molecules used by the endocrine system? Choices: - acids - axons - enzymes - hormones A:
hormones

Q: Why does water have a high surface tension? Choices: - high freezing point - helium bonding - oxygenation - hydrogen bonding A:
hydrogen bonding