Q.Classification based on chromosome is called

When you sort your clothes, you might group them by colour, by season, or by whether they are for work or play — the basis you choose decides how the piles turn out. Classifying living things works the same way: everything depends on what characters we use as the basis for grouping.

Organisms are placed into groups on the basis of their characteristics — the features they show. The more we know about an organism's characters, the more accurately we can see which other organisms it resembles and which it differs from, and so decide where it belongs. Modern classification does not rely on just one kind of feature; it draws on several sources of evidence together:

• External structure — the visible form and shape of the organism.
• Internal structure — how it is built inside.
• Cell structure — features seen at the level of its cells.
• Developmental processes — how it grows and develops.
• Ecological information — how it lives and where it fits in its surroundings.

Interestingly, the earliest attempts at classification used a very different basis: people grouped organisms by their uses — as sources of food, clothing and shelter — because those were their most pressing needs. Only later did interest shift towards the natural relationships among organisms. …