Which of the following correctly displays the sequence of developmental milestones? a) blastula → gastrula → cleavageb) cleavage → gastrula → blastulac) cleavage → blastula → gastrulad) gastrula → blastula → cleavage

Cleavage → blastula → gastrula  correctly displays the sequence of developmental milestones

Explanation:

In first step of developmental milestone, the zygote undergoes cell cleavage to form a spherical balls of cells,  that are known a blastula. This blastula are filled with fluid called blastoderm at the centre. Later the balausta arranges itself in double layer out of which the inner one becomes the zygote and the outer one is placenta. After this stage the blastula folds itself into several layers i.e. germ layers which will give rise to the internal structure of living being. These germ layers are ectoderm, endoderm, mesoderm.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."

answer///multiple alleles;