Question

Pay s -Bone Exam Spring 2030 Psy 101 Take-home Exam Spring 2020 Help Save & El Submit Which of the following statements is true of prenatal development in humans Multiple Choice ) The beginnings of organs appear during the embryon period The rate of cel differenvetion decreases during me embryonic period Oo oo O The inte r act first in the total period of real development ) The fetal period refers to the test and second week of conception < Prev of 100 Next >

Answer 1

The 2nd one is right.

During the first 12 hours after conception, the fertilized egg cell remains a single cell. After approximately 30 hours, it divides from 1 cell into 2 and 15 hours later, the 2 cells divide into 4. And at the end of 3 days, the fertilized egg cell has become a berry-like structure made up of 16 cells. This structure is called a morula, which is Latin for mulberry.

The cells continue to divide 8 or 9 days following conception into a blastocyst. Although it is only the size of a pinhead, the blastocyst is composed of hundreds of cells. The blastocyst is slowly carried by tiny hair-like projections in the fallopian tube called cilia toward the uterus. During the critically important process of implantation, it must attach itself to the uterine lining where it will be able to get nourishment from the mother's blood supply. If the blastocyst is unable to attach, the pregnancy will fail to survive.