Science (English Medium) Class 12 - CBSE Question Bank Solutions for Biology

Define biofertilizers. Give two types of fungal biofertilizers

“The pyramid of biomass is not always upright.” Explain the statement.

Explain the changes that occur in the ovary and uterus during menstrual cycle in human females. Mention the influence of pituitary and ovarian hormones in bringing these changes.

Explain the interrelationship between organic farming and biofertilizers, with the help of any three suitable examples.

How does the activity of each one of the following help in organic farming?
Cyanobacteria

Answer the following question.
How did plant breeding techniques help north Indian farmers to develop cane with desired characters?

Explain the menstruation phases in the menstrual cycle of a human female.

‘A proper understanding of the menstrual cycle can help immensely in family planning.’ Do you agree with the statement? Provide reasons for your answer.

Answer the following question.
What is an ecological pyramid? Compare the pyramids of energy, biomass, and numbers.

Answer the following question.
Write any two limitations of ecological pyramids.

'The pyramid of energy is always upright.' Explain

Explain with the help of labelled diagrams, the difference between an upright pyramid of biomass and an inverted pyramid of biomass.

Define ecological pyramids.

Starting from the innermost part, the correct sequence of parts in an ovule are ______.

Corpus luteum develops under the influence of ______.

Corpus luteum produces ______.

The correct sequence of hormone secretion from the beginning of menstruation is ______.

Immediately after ovulation, the mammalian egg is covered by a membrane known as ______.

The mammalian corpus luteum produces ______.

Secretion of progesterone by corpus luteum is initiated by ______.