Q: In humans, what is the first organ to form and become functional? Choices: - brain - liver - pancreas - heart A:
heart

Q: What is a diagram that shows a single way that energy flows throughout an ecosystem? Choices: - fuel chain - dependent chain - water cycle - food chain A:
food chain

Q: The depth of the atmosphere is greatest where? Choices: - under water - the ionosphere - the stratosphere - sea level A:
sea level

Q: What is the amount of time a molecule stays in a reservoir known as? Choices: - known time - reservoir time - suitable time - residence time A:
residence time