Evolution — BIOLOGY STD 12 Science — Question

Why do pollen grains of some flower trigger sneezing in some people?

From the list of STDs mentioned below, identify the one which does not specifically affect the sex organs.
Syphilis, AIDS, Gonorrhoea, Genital warts.

Write the names of four basics factors that control population density.

Define active immunity.

Give an example of a plant, where the F, progeny of a monohybrid cross has the same genotypic and phenotypic ratios.

What are protected areas?

A human being suffering from Down’s syndrome shows trisomy of 21st chromosome. Mention the cause of this chromosomal abnormality.

If no nutritive substances are secreted by the surface of stigma, what will be its effect on fertilization?

Mark the odd one the following groups.
Fimbriae, Labia minora, Infundibulum, Isthmus.

Give any one example where passive immunisation is needed.