Explain the role of scientist :

$1.$ Francis Crick

$2.$ Friedrich griphith $(1928)$

………. enzymes are used by Avery, Macleod and Mcarty in their experiment

Which of the following is false for $RNA$?

$(i)$ $RNA$ can directly code for the synthesis of proteins

$(ii)$ It is very common process to synthesis $DNA$ from $RNA$

$(iii)$ $RNA$ is used as genetic material only in human

$(iv)$ One polynucleotide chain is present in $RNA$

Which of the following radioactive isotopes were utilised for labelling protein and $DNA$ in transduction experiment respectively?

Who proved that $DNA$ is basic genetic material?