(i) Octopus, cockroach and frog all have eyes.
(ii) Octopus-belongs to mollusc which have simple eye without lens.
(iii) Cockroach are invertebrate have compound eyes.
(iv) Frog which is vertebrate, have highly specialised lens.
(v) However, all of them perform the same function that is vision.
(vi) Thus a common evolutionary origin can be established on the basis of eye.

(i) Fossils are remains or impressions of organisms that lived in the remote past.
(ii) Fossil provide the evidence that the present animal have originated from previously existing ones through the process of continuous evolution.

Yes, he is correct.
Reason: The function of the wings of a crow (the wings of a bird) and wings of an insect are similar, but the basic structure is different.

(i) Astrobiology / Exobiology is the science which looks for the presence of extra terrestrial life in the Universe.
(ii) It deals with the origin, evolution and distribution of life in the Universe and to investigate the possibility of life in other world.
(iii) The major concept is the habitable zone. The theory explains that any planets can support the existence of life, if it fulfills two important criteria, that is :
(a) It must have a right mass to retain an atmosphere.
(b) It must have an orbit at just the right distance from its Star (Sun) that it allows liquid water to exist. Thus, the distance need to be neither too hot or not too cold and is often referred as Goldilock Zone for life.
(iv) In our solar system 'Earth' is the only planet in the Goldilock zone. Since, this zone varies at times as the star evolves, we know that Mars have also been habitable. The life on Mars are likely to be the creatures, we find in extreme environments on earth.

A plant fossil is any preserved part of a plant that has died long back. Fossils may be a prehistoric impression that may be hundred to millions of years old. Majority of the plant fossils are disarticulated parts of plants, it is rare to find plants to be preserved as whole.

These are living organisms that are similar in appearance to their fossilized distant ancestors and, usually have no extinct close features. E.g: Ginko biloba.

Extraterrestrial or Cosmic orgin: Some scientists still believe that life came from outer space. This states that units of life called spores (Panspermia) were transferred to different planets including Earth. This is still an idea of some Astronomers.

(i) Arachaeopteryx.
(ii) It had wings with feathers like a bird.
(iii) It had conical teeth like a reptile.

Yes. When there is a change in the environment, the animals respond to the change. They develop adaptive structures. The characters developed by the animals during their life time, in response to the environmental changes are called acquired characters.
(i) Leo lived in the mountain region and it was wild. It developed hunting skills for survival and this made his legs and body strong. So the muscled physical body, strong legs and hunting skills were the acquired characters inherited by Leo.
(ii) According to Lamarck, the. acquired characters are transmitted to the offspring by the process of inheritance.

Use and disuse theory
(i) Lamarck's Use and Disuse theory states that if an organ is used constantly, the organ develops well and gets strengthened.
(ii) When an organ is not used for a long time, it gradually degenerates.
(iii) The ancestors of Giraffe were provided with short neck and short forelimbs.
(iv) Due to shortage of grass, they were forced to feed on leaves from trees. The continuous stretching of their neck and forelimbs resulted in the development of long neck and long forelimbs which is an example for constant use of an organ.
(v) The degenerated wing of Kiwi is an example for organ of disuse.

The comparative study of Morphology and Anatomy of animals, reveal that they possess common set of characteristics.
(a) Homologous organs:
(i) The homologous organs are those which have inherited from common ancestors with similar developmental pattern in embryos.
(ii) E.g: The fore limbs of mammals are homologous structures. A Human hand, a front leg of a Cat, flipper of a Whale and a Bat's wing look dissimilar and adapted for different functions. Their mode of development and basic structure of bone are similar.
(b) Analogous organs:
(i) The analogous organs look similar and perform similar functions but they have different origin and developmental pattern.
(ii) The function of the wings of a Bat, the wings of a bird and wings of an insect are similar, but their basic structures are different.
(c) Vestigial organs:
(i) The degenerated and non-functional organs of animals are called Vestigial organs. The same organs are found to be well-developed and functional, in some of the related forms.
(ii) E.g: Some of the Vestigial organs in man are Vermiform appendix, Nictitating membrane, Caudal Vertebra, Coccyx etc.
(d) Atavism:
(i) The reappearance of ancestral characters in some individuals is called Atavism.
(ii) E.g: Presence of rudimentary tail in new born babies, presence of thick hair on the Human body.