Researchers discover that a north american bird species called a brown thrasher has a very similar beak structure to one of darwin’s finches. the specialized beak structure, which independently evolved in each species, allows the birds to break open seeds. what terms might relate these two beaks? (select all that apply.)
a. convergent evolution
b. vestigial
c. homologous
d. analogous

The correct answer is a. convergent evolution and d. analogous.

Explanation:

Convergent evolution shows how an organism's trait of one species can be similar to the other species. Therefore in convergent evolution, the same trait is acquired by two species which give them a similar structural form which performs the same function because this form is beneficial for their adaptation in their environment.

Convergent evolution forms analogous structures that mean the structures superficially looks same and do similar function like here brown thrasher has a very similar beak structure to one of Darwin's finches.  

They are different species even then they have a similar beak structure that perform the same function which shows convergent evolution between them. Therefore the correct answer is a and d.

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.