i) Genetics is the mechanism by which variations are created and inherited.

ii) Evolution is used for studying the development of new types of organisms from the existing ones. 

The experiences and qualifications that a person earns during his/her lifetime are examples of acquired traits. These traits cannot be inherited. For example, a wrestler develops large muscles because of his training programme; it does not mean that his offspring will necessarily have large muscles. These characters do not affect the DNA make-up of germ cells of an organism; thus, they are not passed on to the next generation.

(i) The eyes seen in Planaria, insects, octopus and vertebrates vary greatly in their structure. These organisms can be used for studying the evolution of eyes as the eye of Planaria is simple without a lens, insects have compound eyes and vertebrates have highly specialised eyes; however, all of them perform the same function that is a vision. Thus, a common evolutionary origin can be established on the basis of eyes.

(ii) Birds have evolved from reptiles as the connecting link between reptiles and birds is Archaeopteryx (flying dinosaur). Also, there are some similarities in birds and reptiles. Birds have a four-chambered heart, which is also a feature of some reptiles; both birds and reptiles are oviparous and have separate sexes and internal fertilisation occurs in both birds and reptiles.

The process of production of a new DNA molecule from an already existing DNA molecule through chemical reactions is known as DNA copying. It is accompanied by the creation of new cellular apparatus so that the daughter DNA and parent DNA can be separated.

Importance of DNA copying:

1. It helps in the transmission of characteristics from parents to offspring.
2. It helps in the maintenance of the chromosomal number in the new cell.

C.