Which type of circulatory system is shown in the given figure?

$A$ mass $M$ hangs on a massless rod of length $l$ which rotates at a constant angular frequency. The mass $M$ moves with steady speed in a circular path of constant radius. Assume that the system is in steady circular motion with constant angular velocity $\omega$. The angular momentum of $M$ about point $A$ is $L_A$ which lies in the positive $z$ direction and the angular momentum of $M$ about $B$ is $L_B$. The correct statement for this system is

During the first meiotic division,the exchange of genetic material between the chromatids of homologous chromosomes occurs. What is this process called?

Which of the following is the most stable?

Arrange benzene,$n-$hexane and ethyne in decreasing order of acidic behaviour. Also give reason for this behaviour.

Which of the following is not correctly matched?