Answer:
No, they do not have backbones
Explanation:
A,b I think should be the answer
Answer:The respiratory system helps create sound that enables humans to communicate with each another.
Explanation:
Answer:
The correct answer is embroynic stage
Explanation:
The prenatal development is divided into three stages germinal stage, embryonic stage and fetal stage. The period of two weeks after fertilization is called the germinal stage. In this stage, the zygote divided and gets implanted in the uterine wall.
The embryonic stage starts for two weeks and lasts up to 8 weeks after fertilization. At this stage, the cell mass is called embryo. In the embryonic stage, the basic brain structure, CNS, PNS are developed. All the basic organs and body parts develop in this stage except sex organs. So the right answer is the embryonic stage.
