If a growing, potted plant is placed on its side, the stem will grow upwards and the root downwards. This phenomenon called gravitropism causes to inhibit elongation of cells on the surface of roots.

Why do you think the puppy litter was all dark-haired?

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.

Draw the structure of dna nucleotide with adenine as nitrogenous base