On what basis are the three types of lichens classified?

The number of non-empty subsets of the set $\{1, 2, 3, 4\}$ is:

$A$ ball is thrown on a lawn in such a way that it initially slides with a speed $v_0$ without rolling. It gradually picks up rotational motion. Find the speed of the ball at which there will be rolling without slipping.

Which of the following is $NOT$ a part of the intratesticular genital duct system?

$\int(x+1)^2 e^x d x$ is equal to

If the number of diagonals of a regular polygon is $35$,then the number of sides of the polygon is