Form a Hypothesis A scientist uses radioactive nitrogen to label the nitrogenous bases
of the DNA of a cell. Then the DNA is allowed to replicate, and the new strands take up
non-radioactive bases. Do one, both, or neither of the daughter cells have radioactive
DNA? Explain.

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

Compare the composition of the moon's surface with the composition of the earth's surface.

Onsider the paragraph above. what is one chemical property of water? a) water is a polar molecule. b) water is the universal solvent. c) water reacts with group 1 metals. d) water has a high specific heat capacity.