Directional selection I'm pretty sure hope it helps!
The fertilized egg begins a rapid descent to the uterus. The period of rest in the tube appears to be necessary for full development of the fertilized egg and for the uterus to prepare to receive theegg. ... At the end of this transition period, the embryo becomes a mass of very organized cells, called a blastocyst.
Answer:
conformational change in troponin
Explanation:
The troponin complex plays an essential role in the thin filament regulation of striated muscle contraction.
There should be options for this question. I manged to find them elsewhere. They are:
A) the period during which tremendous growth occurs and the organs continue to develop and become functional
B) the period during which the umbilical cord develops
C) the period during which the major organs and structures of the organism first develop
D) the period during which the zygote moves down to the uterus and begins to implant in the lining
The correct answer is C. The embryonic period is the period during which the major organs and structures of the organism first develop. The embryonic period lasts from implantation of the egg in the uterus until about 8 weeks from the time of conception. It is the second major stage of prenatal development, prior to embryonic is the germinal stage and lastly is the fetal stage.
D would be the correct answer
