If two individuals from different species attempt to mate, but fertilization fails to occur, this is likely the result of. However, if such a mating produces a zygote that fails to form a viable embryo, this is likely the result of.
a. pre-zygotic factors; post-zygotic factors.
b. post-zygotic factors; pre-zygotic factors.
c. behavioral factors; pre-zygotic factors.
d. pre-zygotic factors; behavioral factors.
e. post-zygotic factors; lock-and-key factors.

Which of the following is an oxidation-reduction reaction? (pictured below)

The transport tubes for food coming down the plants are called?

Embryonic stem cells are cells derived from an embryo. these cells can be used to create new tissues for patients suffering from certain illnesses and disorders. which statement best summarizes why the use of embryonic stem cells could be seen as unethical? a. some people consider embryos to possess rights equal to those of fully developed human beings. b. extracting stem cells from embryos is a very energy-intensive process, which consumes resources that could be used elsewhere. c. embryos are difficult to obtain, so the monetary cost of using them for research outweighs their benefit. d. the process of extracting stem cells from embryos generates biohazardous waste that cannot be safely disposed of.