Vasoconstriction leads to........

Among the electrolytes $Na_2SO_4$,$CaCl_2$,$Al_2(SO_4)_3$ and $NH_4Cl$,the most effective coagulating agent for $Sb_2S_3$ sol is

If $\Delta$ is the area of the triangle formed by the positive $x$-axis and the normal and tangent to the circle $x^2+y^2=4$ at $(1, \sqrt{3})$,then $\Delta$ is equal to

Acid hydrolysis of $X$ yields two different organic compounds. Which one of the following is $X$?

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?

What is the stored food (nutrient) in algae?