The key lesson learned by the fact that thalidomide showed no impact when tested on prenatal rabbits but led to birth defects in prenatal humans is that

Here are the options.

A. Teratogens impact different genotypes differently.b.teratogens impact specific aspects of development.c.teratogen effects may not emerge until later in life.d.teratogen effects are the same regardless of the time when the individual is exposed.

The key lesson is that teratogens impact different genotypes differently or in different ways.

Explanation:

thalidomide is a tetratogen , a substance that will have a physical or functional defect on an embryo after the pregnant mother is exposed to the substance. This disturb the physical development of the child. It became popular to treat morning sickness in pregnancy but was discovered to result in major limb deformities;

Tetratogen impact different genotypes in different ways because different genotypes have different ways they respond to tetratogens because of their level exposure and subscetability. This the main reason thalidomide showed no impact when tested on prenatal rabbits but led to birth defects in prenatal humans. The genotypes of prenatal rabbits are not subscetiple to tetratogens compare to that of the developing embryo on exposure.

i am positive it is c. condensing but i may be wrong