The most stable carbocation among the following is:

1.	`	2.
3.		4.

The molecule among the following that has the hybridization ${\mathrm{sp}}^2,\hspace{0.17em}{\mathrm{sp}}^2,\hspace{0.17em}\mathrm{sp},\; and\hspace{0.17em}\mathrm{sp}$ from left to right atoms is:

1. $\mathrm{HC}\equiv \mathrm{C}-\mathrm{C}\equiv \mathrm{H}$

2. ${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{C}\equiv \mathrm{CH}$

3. ${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{CH}={\mathrm{CH}}_2$ 

4. ${\mathrm{CH}}_2-\mathrm{CH}=\mathrm{CH}-{\mathrm{CH}}_3$

The experimental proof for semiconservative replication of DNA was first shown in a:

1. Fungus

2. Bacterium

3. Plant

4. Virus

Offsets are produced by:

Select the correct match:

1. Alec Jeffreys – Streptococcus pneumoniae

2. Alfred Hershey and Martha Chase – TMV

3. Matthew Meselson and F. Stahl – Pisum sativum 

4. Francois Jacob and Jacques Monod – Lac operon 

Which of the following has proved helpful in preserving pollens as fossils?