When two frog species, rana pipiens and rana sylvatica, mate, the offspring die early in embryonic development. this is an example of
a) hybrid sterility
b) reduced hybrid fertility
c) reduced hybrid viability
d) mechanical isolation

The correct answer is c) reduced hybrid viability.

Explanation:

As the offspring dies early in embryonic development, it's possible to understand that the organism isn't viable, which is very common among hybrid organisms as well as their sterility or reduced fertility.

wheres the answers ?

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.