$A$ pair of insectivorous plants is

There are $3$ sections in a question paper and each section contains $5$ questions. $A$ candidate has to answer a total of $5$ questions,choosing at least one question from each section. Then the number of ways,in which the candidate can choose the questions,is

Which of the following species has the highest electron affinity?

If the direction cosines of two lines are given by $l+m+n=0$ and $l^2-5m^2+n^2=0$,then the angle between them is

$A$ gas is compressed at a constant pressure of $50 \ N/m^2$ from a volume of $10 \ m^3$ to a volume of $4 \ m^3$. Energy of $100 \ J$ is then added to the gas by heating. Its internal energy is:

If $a > 0$ and $\lim _{x \rightarrow a} \frac{a^x - x^a}{x^x - a^a} = -1$,then $a$ is equal to