3/10 why did earth's early atmosphere lose its hydrogen and helium gases? a. the gases were too light to be held by gravity. b. the gases condensed, forming oceans, rivers, and lakes. c. the planet was so hot that all gases escaped into space. d. the gases were replaced by carbon dioxide from volcanic eruptions.

Astudent wants to test the hypothesis that fertilizer improves the growth rate of grass seeds. to test this hypothesis, the student put the same amount of grass seed in 3 containers with the same type of soil. the student measured the growth at the end of the week. all plants received equal amounts of water and sunlight. if you were asked to graph this data, what would you place on the x-axis? a. fertilizer b. water c. plant growth d. week one

Is a measure of the different types of organisms in a community. question options: tertiary secondary primary none of the above

What are the subsystem of the earth