HELP PLS Definition: This is the growth or movement of a organism (usually a plant), in response to a stimulus. Example: The stimulus can be gravity, light, touch, or temperatre.

Where do homologous chromosomes exchange genetic material through crossing over?               a.  chlorophyll    b.  centrosomes    c.  centromeres    d.  chiasma

Acertain species of fish can have either long or short fins. the allele for long fins is dominant over the allele for short fins. a heterozygous, long-finned fish is crossed with a homozygous, short-finned fish. of the offspring, will have long fins and be , and will have short fins and be .

Radiometric dating is used to tell the absolute age of materials by studying the decay rate of radioactive isotopes. the decay rates of isotopes are constant and are expressed as .