Before there was any life on earth, which gas was absent from the ancient atmosatmosphere?
1)oxygen
2)ammonia
3)nitrogen
4)methane

Which statement best explains how cellular respiration maintain homeostasis in animals? it maintains body temperature by absorbing energy. it breaks glucose into energy required by the organism. it speeds up metabolism by making oxygen. it produces energy from hormones present in the organism.

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils

Sexual reproduction in the parent cell will result in offspring with a) identical genetic information. b) half the genetic information. c) double the genetic information. d) four times the genetic information.