What causes ozone depletion?
a. flying airplanes especially at high altitudes.
b. combustion of a sulfur containing fuel like coal.
c. cfcs leaking from old refrigerators and air conditioners.
d. deforestation especially in mountainous regions.

Which supports the idea that birds and butterflies both have wings but they do not have a common ancestor with wings? the wings are analogous structures that evolved differently and do not have a similar internal structure. the wings are homologous structures that evolved differently and do not have a similar internal structure. wings of birds are vestigial structures, but the wing structures of bats are not vestigial. wings of bats are vestigial structures, but the wing structures of birds are not vestigial.

All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.

Variety of living organisms; includes genetic, species, and ecological types.