Differentiate between a DNA and a RNA nucleotide.

Why are no variations seen in clones? State two reasons.

What is ‘Saltation’ according to de Vries?

Write the scientific name of the organism Alexander Fleming worked on and discovered the first antibiotic. Was the organism he worked on a fungus or a bacterium?

OR

Suggest a method to overcome excessive inbreeding depression.

Name the pollutant attributed to be the cause of ‘ozone-hole’ over the Antarctica region.

OR

List the greenhouse gases other than carbon dioxide.