Tag: botany

Enormous amount of yolk is present in megalecithal eggs and here yolk is several times greater than cytoplasm and yolk is concentrated in the interior of the egg and the cytoplasm is distributed as a thin layer on the outside of the yolk in centrolecithal eggs. These type of eggs is a characteristic of insects. Hence, option C is correct.

Mesolecithal egg are those eggs that has a yolk of intermediate size and strongly concentrated in one hemisphere. The young hatch at a later stage of development. It is a characteristic of lung fishes and amphibians likes frog. Hence, option B is correct.

Enormous amount of yolk is present in megalecithal eggs and here yolk is several times greater than cytoplasm. These eggs may be small or big. These types of eggs are characteristics of of teleost fishes, reptiles, birds. Yolk of egg is used for two purposes; supply of energy and synthesis of the products required for elaboration of the embryonic body.

• Reproduction is the biological process in which new individual organisms 'offsprings' are produced from their parents (existing organisms).

• Development is the act or process of growing or causing something to grow or become larger or more advanced.

Mutations are the permanent changes in the nucleotide sequence of the genome of an individual. These can occur during replication of DNA or its exposure with radiations or carcinogens, etc.

The life span of dog is 16 - 18 years. Life expectancy in dogs can be affected by many factors including genetic disease, diet, and exercise, similar to humans. Life expectancy usually varies within a range. For example, a Beagle (average life expectancy 13.3 years) usually lives to around 12–15 years, and a Scottish Terrier (average life expectancy 12 years) usually lives to around 10–16 years.

A woman is fertile, on average, between the ages of $12$ to $15$. During these fertile years, a recurring process - known as the menstrual cycle - takes place each month. This involves the lining of the uterus preparing for pregnancy. If pregnancy does not occur, the lining breaks down and the woman has a period. This is also known as menstruation. During this period which is generally from day $1$ to the day $7$ of the cycle, the intercourse does not result in pregnancy.

In women, both sex chromosomes are the same and are therefore called as XX. In males, they are different and called as XY. When sperm and eggs (ova) are made during meiosis they separate to form different gametes. As women have XX, their eggs always carry the X chromosomes. As males have XY, approximately half their sperm carry the X chromosome while the remainder carries the Y chromosome.