In which of the following is the gametophytic phase dominant?

Which of the following pairs of species is used in the preparation of antacid medicines?

The angle between a pair of tangents drawn from a point $P$ to the circle $x^{2}+y^{2}+4x-6y+9 \sin^{2} \alpha + 13 \cos^{2} \alpha = 0$ is $2 \alpha$. The equation of the locus of the point $P$ is

Two blocks $A$ and $B$ of masses $1\,kg$ and $2\,kg$ are connected together by a spring and are resting on a horizontal surface. The blocks are pulled apart so as to stretch the spring and then released. The ratio of $K.E.s$ of both the blocks is

Two rods of the same length and material transfer a given amount of heat in $12 \, s$,when they are joined in parallel. But when they are joined in series,then they will transfer the same amount of heat under the same conditions in ......... $s$.

Which of the following statements is incorrect?