Q: Three distinct layers or tunics form the walls of what structures; the first is a smooth, inner lining of endothelial cells in contact with the red blood cells? Choices: - lungs - white blood cells - alveoli - blood vessels A:
blood vessels

Q: Loss of energy is the reason that what typically has few levels? Choices: - humans - the atmosphere - video games - food chain A:
food chain

Q: Q: Monoecious flowers are also known as "perfect" flowers because they contain both types of what organ? Choices: - vascular organ - respiratory organ - phloem - sex organ A:
A: sex organ

Question: Q: The combustion of propane gas produces carbon dioxide and what else? Choices: - methane - carbon monoxide - phosphorous - water vapor A:
Answer: water vapor

*Question*
Q: What type of rock is a sandstone? Choices: - igneous rocks - landform rocks - limestone rocks - sedimentary rocks A:
**Answer**
sedimentary rocks

*Question*
Q: What blood pressure reading measures the pressure in the vessels between heartbeats? Choices: - metabolic - plasma - systolic - diastolic A:
**Answer**
diastolic