How do animals reproduce? - class-IX

Cowper's glands (also known as bulbourethral glands) are a pair of exocrine glands in the male reproductive system of many mammals, which secrete a fluid that neutralizes acidity in the urethra.

Parthenogenesis is a form of asexual reproduction where an embryo develops from an unfertilized egg cell. Since none of the specific options (female gametes, vegetative cells, fertilized ovum) accurately describe the process of development from an unfertilized egg, 'None of these' is correct.

In the bed bug, the sex determination system is XO for the female and XX for the male, which is the reverse of the typical XY system found in humans.

• Yeasts are fungi that grow as single cells, producing daughter cells either by budding (the budding yeasts) or by binary fission (the fission yeasts)
  
• A small bud which will become the daughter cell is formed on the parent (mother) cell and enlarges with continued growth. As the daughter cell grows, the mother cell duplicates and then segregates its DNA. The nucleus divides and migrates into the daughter cell.
• Hence Budding in Yeast is the correct mode of reproduction.
• So, the correct answer is 'Budding in Yeast'.

Certain animals like earthworm have both the sexes i.e., male and female reproductive system in one body itself. Such organisms are called as hermaphrodite. They tend to reproduce sexual by copulating.

Discoblastula is disc shaped blastula which is formed by meroblastic discoidal cleavage as in fishes, reptiles, birds and egg laying mammals.

Sertoli cells are non-gametic cells in the seminiferous tubules which provide nourishment for developing sperms.

Entrance of a single sperm into an oocytes called monospermy generally monospermy is found in most of the animals. Cortical granules are extruded in the perivitelline space by exocytosis and some of these are attached along the inner surface of vitelline membrane which now thickens and becomes impervious to any other sperm entry. It is now called fertilization membrane. It prevents the polyspermy.

Testes in mammals are present out side the abdominal cavity because maturation of sperm needs low temperature. The temperature of scrotum is below (2 to 4$^{o}C$) than abdominal cavity.

Zygote divide vertically to form two blastomeres. This is followed by a vertical division and a horizontal division. Now, several divisions occur forming equal sized blastomeres called morula. There is no increase in size of cells. Zona pellucida is a transparent non cellular layer surrounding egg cell. It remains undivided till the cleavage is complete.

In crocodilians, sex determination is temperature-dependent. Males are typically produced at higher temperatures, while females are produced at lower temperatures.

Reproduction is a biological process by which new individual organism is produced from their parents. Reproduction is a fundamental feature of all life. Reproduction helps the species to live a long period of life. Sexual reproduction also links with a variation in species which help in them for survival. 

• A human being a complex eukaryotic organism with a well developed reproductive system have greater reproductive potential and since the variation is seen in the offspring chances of survival are most.
  

The testes in mammals are located outside the body cavity in the scrotum because spermatogenesis requires a temperature slightly lower than the core body temperature.

Indigenous species are the ones that are found naturally in a particular habitat or they are native to that place.

Asexual reproduction is also called somatogenic reproduction, in these new organisms are produced from the somatic part of the parent organism.