Which of the following is in the correct order of the three periods in prenatal development from conception to birth? group of answer choices
a. gestational, germinal, postnatal
b. germinal, embryonic, fetal
c. preterm, germinal, postterm
d. fertile, embryonic, postterm

b.Germinal, embryonic, fetal

Explanation:

The period from conception to birth generally includes the order that is germinal, embryonic and fatal.

Germinal period: It begins with the rapid cell division and differentiation of the blastocyst which is a cell mass acts as a precursor of new life. The germinal period last for 2 weeks.

Embryonic period: This period lasts for 8-10 weeks. In this period a process called as gastrulation occurs in which the three layers called as germ layers develop. The ectoderm is the outer layer, the mesoderm is the middle layer and the endoderm is the inner layer. Each germ layer differentiate into different structures.  

Fetal period: It is the final stage of development of the fetus. It last for 10-40 weeks of pregnancy. It initiate from the embryonic period till the birth of the full term fetus. It involves the development and specializing of structures. Organ system of the fetus develops in this stage.

a and c are the answeres

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.