4. a new species forms because of the formation of a mountain that divides one population into
two. what type of speciation is this?
5. the bell curve in polygenic traits is becoming narrower over time. what type of selection is
occurring?
6. what are the five conditions impacting the hardy-weinberg equilibrium?
7. how does natural selection impact single-gene traits?
8. what does the allele frequency have to total in the hardy-weinberg equilibrium?

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.

Ry was studying two populations of the same species of lizards. one population lived on an island and the other lived on the mainland. both populations were affected by a hurricane that hit the island and the mainland with equal force. a year later, henry was testing the gene frequency and saw a decrease in genetic variation in the island species, but not in the mainland species. which best describes a conclusion he might have reached? gene flow greatly affects small populations, but large populations can recover. genetic drift greatly affects small populations, but large populations can recover. gene flow greatly affects large populations, but small populations can recover. genetic drift greatly affects large populations, but small populations can recover.

Where do the respiratory and circulatory systems meet? a. in the heart b. in the muscles c. in the lungs d. in the brain