Which of the following is not an example of a natural polymer?

During transcription,the holoenzyme $RNA$ polymerase binds to a $DNA$ sequence,and the $DNA$ assumes a saddle-like structure at that point. What is that sequence called?

$A$ large horizontal surface moves up and down in $SHM$ with an amplitude of $1 \, cm$. If a mass of $10 \, kg$ (which is placed on the surface) is to remain continually in contact with it,the maximum frequency of $SHM$ will be ... $Hz$.

Which of the following species has the highest electron affinity?

Refer to the botanical name of wheat "$Triticum\; aestivum$" and identify the statement which correctly describes it.

In the given figure,a ring of mass $m$ is kept on a horizontal surface,while a body of equal mass $m$ is attached through a string wound on the ring. When the system is released,the ring rolls without slipping. Consider the following statements and choose the correct option.
$(i)$ Acceleration of the centre of mass of the ring is $g/3$.
$(ii)$ Acceleration of the hanging particle is $2g/3$.
$(iii)$ Frictional force (on the ring) acts along the forward direction.
$(iv)$ Frictional force (on the ring) acts along the backward direction.