Which of the following is a branch of biology?

${ }^{15}P_8 = A + 8 \cdot { }^{14}P_7 \Rightarrow A = $

The second and third rows of transition elements resemble each other much more than they resemble the first row. Explain why?

Three unequal resistors in parallel are equivalent to a resistance $1 \, \Omega$. If two of them are in the ratio $1 : 2$ and if no resistance value is fractional,the largest of the three resistances in $ohms$ is

If $f: R \rightarrow R$ is defined by $f(x) = \begin{cases} \frac{\cos 3x - \cos x}{x^2}, & \text{for } x \neq 0 \\ \lambda, & \text{for } x = 0 \end{cases}$ and if $f$ is continuous at $x = 0$,then $\lambda$ is equal to

The radius of the circle $r = \sqrt{3} \sin \theta + \cos \theta$ is