Reproductive Health — BIOLOGY STD 12 Science — Question

Why do we prefer to call secondary waste water treatment as biological treatment?

What kind of organs are the thorn of Bougenvillia and the tendril of cucurbita? What type of development has brought about such similarity in them?

Write one method of introducing foreign DNA into host cells.

Due to whose efforts was the technology of biogas production developed in India?

When does the human beings elicit an anamnestic response? or Suggest a method to ensure an anamnestic response in humans.

Why is X-chromosome called sex chromosome?

Write the names of two main groups of cells required to achieve specific immunity.

When did the jawless fish evolve?

How can pregnancy due to unprotected sex be prevented?

Mention two environmental factors that affect pollen viability.