Reproduction in Organisms Test 3

• Embryo sac is formed in the ovule by the process of megasporogenesis and megagametogenesis.
• During megasporogenesis, a diploid megaspore mother cell undergoes meiosis to form four haploid megaspores.
• Three of these megaspores degenerate and one remains functional. The functional megaspore then develops into embryo sac or the female gametophyte and this is known as megagametogenesis.
• The functional megaspore nucleus undergoes 3 meiotic divisions without cell wall formation and this results in 8 nuclei which get organized into egg apparatus, antipodal cells and the central cell. This forms a 7-celled but 8-nucleate structure which is the female gametophyte or embryo sac.

Thus, embryo sac occurs in the ovule.
So, the correct answer is B.

Embryo Sac:

Pregnancy, also known as gravidity or gestation. The pregnancy period is classified into three Trimester.

They are as follows:

• First Trimester (0 to 13 Weeks).
• Second Trimester (14 to 26 Weeks) is often called the "golden period" because many of the unpleasant effects of early pregnancy disappear.
• Third Trimester (27 to 40 Weeks).

• The average length of the menstrual cycle is 28–29 days, but this can vary between women and from one cycle to the next.
• The length of your menstrual cycle is calculated from the first day of your period to the day before your next period starts.

• In biology, a hermaphrodite  is an organism that has complete or partial reproductive organs and produces gametes normally associated with both male and female sexes. 
• Many taxonomic groups of animals (mostly invertebrates) do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the "female" or "male." For example, the great majority of tunicates, pulmonate snails, opisthobranch snails, earthworms and slugs are hermaphrodites.
• Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites.

• The urethra is the tube that carries urine from the bladder to outside of the body.
• In males, it has the additional function of ejaculating semen when the man reaches orgasm.
• When the penis is erect during sex, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.

Therefore, Option D is the correct answer.

• External fertilization occurs mostly in wet environments and requires both the male and the female to release their gametes into their surroundings (usually water).
• An advantage of external fertilization is that it results in the production of a large number of offspring.
• One disadvantage is that environmental hazards such as predators greatly reduce the chance of surviving into adulthood.
• Amphibians and fish, aquatic algae are examples of animals that reproduce this way.

So, the correct option is 'algae'.

There are 3 phases in a life cycle:

1. Juvenile phase/ vegetative phase: Period from birth to maturation of reproductive systems.
2. Reproductive Phase: Period when the reproductive systems have matured and ready to produce offspring.
3. Senescence: Period when the organism starts growing old and starts degrading.

• Sexual reproduction leads to new genetic combination leading to variation in new products.
• The longer viability of seeds, prolonged dormancy and large biomass are not related to sexual reproduction.