What is the full form of $EtBr$?

If a double stranded $DNA$ has $20$ percent of cytosine,calculate the percent of adenine in the $DNA$. (in $\%$)

Which of the following statements is correct regarding a substance?

It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material. This is written by

Which is known as soluble $RNA$?

State the physical structure of $DNA$.