Fertilized egg (also called zygote) reaches uterus, particularly at blastocyst stage (approximately 5 to 6 days post fertilization) and gets adhered to the uterine wall and from now it is considered as embryo. This process is known as implantation.
During the stage of prenatal development, the growing embryo receives nutrients and oxygen from the mother through placenta and develops into fetus (8th week post fetilization, which is 10th week of pregnancy). Fetus grows within uterus till the last week of pregnancy that is around 38 weeks.
Thus, uterus is the right answer for the given blank.
A fertilized egg usually implants itself and develops in the uterus. <span>During the prenatal development, fertilized egg adheres to the wall of the uterus. Zygote (fertilized egg) at this stage forms blastocyst. The blastocyst consists of an inner cell mass and the outer layer -the trophoblast. Trophoblast surrounds the inner cell mass and a fluid-filled cavity - blastocoele. Inner cell mass will form embryo and trophoblast gives rise to the placenta.</span>
Salt concentration is the factor among the following factors given in the question that does not vary between a fast flowing river and a pond that receives no water input. The correct option among all the options that are given in the question is the second option. I hope the answer comes to your help.
