Correct passage of sperm:

Testis → epididymis → vas deferens → ejaculation duct → urethra → penis

The oogonium and primary oocyte are diploid cells. The secondary oocyte, first polar body, ovum, and second polar body are haploid cells.

When sperm and egg meet, it comes to be a zygote and is then implanted in the lining of the uterus. During this time the corpus luteum keeps releasing estrogens and progesterone for promoting uterine lining growth. Increased secretion of LH and FSH does not occur.

Two identical embryos from a single zygote, one egg and sperm, is called identical twins. However, they are not exactly same because they get different amounts of nutrients from the mother and they even develop in slightly different environments.

The respiratory system, digestive system, and urinary bladder are derived from endoderm. The somite and notochord are derived from mesoderm.

Zona pellucida is the extracellular matrix of egg for sperm receptor of internal fertilization of mammals.

All are true. Acid secretion of the vagina functions in disinfection.

The epidermis of skin is derived from ectoderm and the rest of the above are derived from mesoderm.

The maternal arteries and umbilical veins are afloat in sinus containing maternal blood, and they are connected indirectly.

Cell differentiation means that a single zygote becomes a specialized system of tissues in multicellular organisms. Induction means that one part of embryonic cells influence the growth of another. Morphogenesis means that the differentiated cells are placed at proper locations. Substances that regulate differention of embryonic cells are called cytoplasmic determinants.

The head of the sperm has an acrosome to penetrate the envelop of the egg and insert the nucleus into the egg.

The Fallopian tube, also called the oviduct, is place of fertilization and passage of the egg.

The corpus luteum secretes estrogen and progesterone.

Cortical reaction is when the release of a cortical granule transforms the vitelline layer into a fertilization envelope and causes a slow block to polyspermy. A is the contact stage and B is depolarization. E is the acrosomal reaction.

The plasma membrane is fused by the inserted sperm nucleus, which causes the membrane to be potentially charged and then the fast block to polyspermy occurs.

Correct order of embryonic developmental stages:

Cleavage(morulation → blastulation) → gastrulation → organogenesis(neurulation, induction)

Correct passage of placental circulation:

Maternal arteries → umbilical veins → embryo → umbilical arteries → maternal veins

After birth the infant begins producing hemoglobin, degenerating the foramen ovale, increasing the pressure of the left atrium, and decreasing the pressure of the right atrium and pulmonary arteries.

All are true exceptⅡ. Unlike oogenesis in the female, the equally distributed cytoplasm happens in spermatogenesis in the male.

After ovulation the corpus luteum secretes estrogen and progesterone for preparing the uterine lining for growth and implantation of the zygote.

After fertilization many reactions of DNA synthesis and mitosis happen. Meiosis only occurs in the ovary of the female and seminiferous tubules of the male.

A blastula of the cleavage stage forms a hollow ball of cells and blastocoels (fluid-filled cavities). A morula of the cleavage stage forms a solid ball of cells. A gastrula forms three germ layers (ectoderm, mesoderm, and endoderm). The blastopore is the end of archenterons, becoming a protostomal mouth or deuterostomal anus. The stage of organogenesis forms the different rudiments of organs from the three germ layers.

York sac provides nutrients to embryo. Allantois is a disposal sac for liquid waste from embryo and functions in respiration. Chorion is membrane for exchanging gases between embryo and outside membrane. Amnion is membranous sac for protecting an embryo from mechanical shock and dehydration.

All are correct except D. The Vas deferens is a duct for expulsion of sperm. The place for storage and maturation of sperm is the epididymis.

Estrogen and progesterone inhibit secretion of LH and FSH hormones, which stimulate ovaries in the process of ovulation.

The peak of LH and FSH happens just before ovulation and the peak of progesterone and estrogen happens before maximum thickening of the endometrium.

Epidermis of skin, sensory receptor, nervous system, and teeth are derived from ectoderm.  Circulatory system (heart, blood vessels) and muscular system are derived from mesoderm. Respiratory system (lungs) and digestive system (pancreas) are derived from endoderm.

During gastrulation the process of invagination becomes a dorsal lip and forms a U-shaped structure of archenterons and three germ layers (ectoderm, mesoderm, endoderm). The neural tube forms late in neurulation.

Amnion is not present in amphibian eggs laid in the environment of water.

At the placenta, a fetus obtains nutrients from maternal arteries and excretes wastes to maternal veins.

FSH secreted by the anterior pituitary and testosterone secreted by Leydig cells regulate spermatogenesis. The flagellum is worked by ATP, which is produced by many mitochondria in the sperm.

Allantois functions as a disposal sac for wastes and respiration in shelled eggs. It becomes the placenta in mammals.