Environmental Issues — BIOLOGY STD 12 Science — Question

How many meiotic divisions are necessary for the formation of 100 pollen grains:

Ingestion of marijuana leads to illusions and alters the thoughts, feelings and perceptions of a person. Marijuana is a

The natural method of pest and pathogen control involving use of viruses, bacteria and other insects is called

Diaphragms are contraceptive devices used by the females. Choose the correct option from the statements given below:

1. They are introduced into the uterus.
2. They are placed to cover the cervical region.
3. They act as physical barriers for sperm entry.
4. They act as spermicidal agents.

The genotype of a boy having sexual characters of a girl is

Darwin’s finches provide an excellent evidence in favour of evolution. This evidence comes from the field of:

Methanogens, growing anaerobically on cellulosic material, produce

The end of vegetative phase in plants which marks the beginning of the reproductive phase can be easily seen in the higher plants when they come to: