Earth’s helps protect life from ultraviolet radiation. Earth’s atmosphere is mostly made up of the gases and .

There is some evidence to suggest that Mars once had liquid , though now it may be trapped as .

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.

my teacher would say no s

flooding wildfire landslides climate change the factors listed have an immediate effect on the animal populations found in any habitat. the four factors would lead to a death. b emigration. eliminate c immigration. d mutations.