Birds and humans are theorized to have a common ancestor because they have homologous structures. Which evidence best supports this theory? They both have tails and embryos. They each have vestigial structures. They have analogous structures. They have different forms as adults.

They each have vestigial structures.

Explanation:

Birds and humans have a common ancestor as they have homologous structures.

Vestigial structures are the organs that have some important functions in the past but now in present, they do not perform any function.

Both humans and birds have vestigial structures such as humans have an appendix and ear pinna and wings of flightless birds such as ostrich.

Hence, the correct answer is "They each have vestigial structures.".

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

b.