Germ layers form during the <u>germinal </u>period while organ systems mature during the <u>fetal</u> period.
The endoderm (inner layer), ectoderm (outer layer), and mesoderm are the three major cell layers that make up the germ layer. They arise in the early stages of embryonic development (middle layer).
The first two weeks following conception are known as the germinal stage, followed by the embryonic phase from the third to the eighth week, and the fetal period, which lasts from the ninth week until delivery.
A variety of procedures take place during the germinal stage to transform an egg and sperm first into a zygote and later into an embryo. The procedures include implantation, blastulation, cleavage, and fertilisation.
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Explanation:
The united states of america
D. The process of becoming a citizen in a country
It's because the definition of "naturalization" would mean the admittance of a foreigner to the citizenship of a country.
Ex.
"an application for naturalization as a american citizen"
