During a thunderstorm, an observer can see lightning before hearing its thunder. Why do we see lightning before we hear thunder? O Sound travels slower than light
O Sound needs a medium to travel through.
O Sound cannot reflect off surfaces as easily as light.
O Sound is not processed by the brain as fast as light.

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.

What noticeable trend from this graph might be used to make a conclusion?

About how much of the cell mass is watet