According to the $1991$ census,the number of females per $1000$ males is:

Given below are two statements,one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A):$ Adolescence means both 'a period' and 'a process' during which a child becomes mature in terms of his/her attitudes and beliefs for effective participation in society.
Reason $(R):$ The period between $12-18$ years of age may be thought of as the adolescence period.
In the light of the above statements,choose the most appropriate answer from the options given below:

The permissible use of the technique amniocentesis is for

Given below are two statements with respect to amniocentesis.
Statement $I$: Amniocentesis is a process in which amniotic fluid containing foetal cells is collected using a hollow needle inserted into the uterus.
Statement $II$: $X$-ray imaging is used to determine the position of the foetus in the uterus.
In light of the above statements, select the correct answer from the options given below.

Which of the following cannot be detected in a developing foetus by amniocentesis?

What care should be taken when choosing a contraceptive method?