In which of the following pairs of categories is it more difficult to determine the relationship to other taxa at the same level, thus making the problem of classification more complex?

Which substance is in higher concentration in blood than in glomerular filtrate?

Genus represents

Box $A$ contains $2$ black and $3$ red balls, while Box $B$ contains $3$ black and $4$ red balls. Out of these two boxes, one is selected at random; and the probability of choosing Box $A$ is double that of Box $B$. If a red ball is drawn from the selected box, then the probability that it has come from Box $B$ is:

The angle between the asymptotes of the hyperbola $x^2-3y^2=3$ is

If $f: R \rightarrow R$ is an even function having derivatives of all orders,then which of the following is an odd function?