Question

1. during the first three days of development, the developing human embryo obtains nutrients and energy from the:

a. hcg from the corpus luteum
b. fluid from the amniotic sac
c. mitochondria of what was the fathers sperm
d. cytoplasm of what was the mothers egg

1. a thick and vascularized (large blood supply) endometrium

a. remains when progesterone levels and estrogen levels both decrease.
b. is present when an egg is fertilized and progesterone levels remain high.
c. is present when an egg is fertilized and progesterone levels decrease.
d. remains when progesterone levels decrease and estrogen levels remain high.

1. choose the process that best describes how the three primary germ layers are formed.

a. cleavage and gastrulation
b. parturition and lactation
c. gastrulation and implantation
d. fertilization and cleavage

1. human development begins with fertilization. which row below identifies the structure in which fertilization takes place and the number of chromosomes that are found in the fertilized egg?

row structure number of chromosomes in fertilized egg
a. uterus 46
b. uterus 23
c. oviduct 46
d. oviduct 23

Explanation:

Question 1

The developing human embryo in the first three days gets nutrients and energy from the cytoplasm of the mother's egg. The egg has stored nutrients. HCG (human chorionic gonadotropin) from the corpus luteum is involved later in maintaining pregnancy. The amniotic sac fluid is for protection and cushioning later. The father's sperm mitochondria are usually degraded.

When an egg is fertilized, the corpus luteum (maintained by HCG) continues to produce progesterone. Progesterone keeps the endometrium thick and vascularized (with a large blood supply) to support the developing embryo. If progesterone levels decrease (when there is no fertilization), the endometrium sheds.

Gastrulation is the process by which the three primary germ layers (ectoderm, mesoderm, endoderm) are formed. Cleavage is the early cell - division process of the zygote. Parturition is childbirth and lactation is milk - production. Implantation is the embedding of the blastocyst in the endometrium. Fertilization is the fusion of gametes.

Answer:

D. cytoplasm of what was the mother's egg

Question 2