Which of the following animals is not viviparous?

$A$ block of mass $m=25 \ kg$ sliding on a smooth horizontal surface with a velocity $v=3 \ ms^{-1}$ meets a spring of spring constant $k=100 \ N/m$ fixed at one end as shown in the figure. The maximum compression of the spring and the velocity of the block as it returns to the original position are respectively:

Two gases $A$ and $B$ having the same volume,effuse through an orifice in $30 \ min$ and $10 \ min$ respectively. The molar mass of $A$ is $162$. The molar mass of $B$ will be

Consider the statements given below regarding contraception and answer as directed thereafter:
$(1)$ Medical Termination of Pregnancy $(MTP)$ during the first trimester is generally safe.
$(2)$ Generally,chances of conception are nil until the mother breast-feeds the infant up to two years.
$(3)$ Intrauterine devices like Copper-$T$ are effective contraceptives.
$(4)$ Contraception pills may be taken up to one week after coitus to prevent conception.
Which two of the above statements are correct?

$A$ force $F$ is applied on a square area of side $L$. If the percentage error in the measurement of $L$ is $2 \%$ and that in $F$ is $4 \%$,what is the maximum percentage error in pressure?

The binomial coefficients which are in decreasing order are