Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Biology

When and where do chorionic villi appear in humans?

Name any two sources of e-Wastes and write two difference ways of their disposal.

Comment on the role of placenta as an endocrine gland.

During the reproductive cycle of a human female, when, where and how does a placenta develop? What is the function of placenta during pregnancy and embryo development?

Arrange the following hormones in sequence of their secretion in a pregnant woman. 

hCG, LH, FSH, Relaxin

State the Function of Chorionic Villi

Medically it is advised to all young mothers that breast-feeding is the best for their newborn babies. Do you agree? Give reasons in support of your answer.

An electrostatic precipitator in a thermal power plant is not able to generate a high voltage of several thousand. Write the ecological implication because of it.

Gonads develop from embryonic ______.

Which of the following hormones is not secreted by human placenta?

Eye lens is formed from ______.

Which extra-embryonic membrane in humans prevents desiccation of the embryo inside the uterus?

The first movements of the foetus and appearance of hair on its head are usually observed during which month of pregnancy?

Distance between the genes and percentage of recombination shows ______.

Occasionally, a single gene may express more than one effect. The phenomenon is called ______.

Which of the following hormones is not a secretory product of human placenta?

Urine test during pregnancy determines the presence of ______.

In the event of pregnancy, the corpus luteum persists under the influence of ______.

In the development of the human body, the ectoderm is responsible for the formation of ______.

The early stage human embryo distinctly possesses ______.