Ephemerals are xerophytes that are:

Which of the following factors are favourable for the formation of oxyhaemoglobin in alveoli?

Which of the following equations represents a circle?

$A$ satellite of mass $m$ is in a circular orbit of radius $2R_E$ about the Earth. The energy required to transfer it to a circular orbit of radius $4R_E$ is (where $M_E$ and $R_E$ are the mass and radius of the Earth respectively).

The reading of a spring balance corresponds to $100 N$ while situated at the north pole and a body is kept on it. The weight record on the same scale if it is shifted to the equator, is $...........\,N$

(take, $g =10 m / s ^2$ and radius of the earth, $R =6.4 \times 10^3 m$ )

For any integer $n \geq 1$,the number of positive divisors of $n$ is denoted by $d(n)$. Then,for a prime $P$,$d(d(d(P^7)))$ is equal to