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

If the radius of a star is $R$ and it acts as a black body,what would be the temperature of the star,in which the rate of energy production is $Q$? ( $\sigma$ stands for Stefan's constant.)

Which of the following statements are correct?
$(i)$. Genus comprises a group of related species.
$(ii)$. Taxon represents a taxonomic group of individual organisms.
$(iii)$. Family comprises a group of related genera.
$(iv)$. Taxonomic category class includes related orders.

Two non-reactive monoatomic ideal gases have their atomic masses in the ratio $2 : 3$. The ratio of their partial pressures,when enclosed in a vessel kept at a constant temperature,is $4 : 3$. The ratio of their densities is :-

Which of the following reactions occurs at the cathode during the charging of a lead storage battery?

If the number of diagonals of a regular polygon is $35$,then the number of sides of the polygon is