Question

why we always study biology by comparing humans with rabbit and frog why not we compare humans with lion,etc why we always study biology by comparing humans with rabbit and frog why not we compare humans with lion,etc @Biology

Answer 1

Why not compare to plants or microbes?

Answer 2

for various reasons, some meaningful, some prosaic:
*ethics of animal handling for research require the lowest number of the lowest developmental stage relevant.
*the animals, or rather animal models we study are the ones we tend to compare to.
some animals are just better models. for reasons of cost, ease of handling, short fertility cycles, relatively quick puberty, size - sometimes small is useful, sometimes big isbetter (for surgical procedures).
cats are models mostly for hearing and eyseight - coming back to lions, developmentally they are more or less like cats, but they are harder to handle and more expensive - so why bother.

the classic models:
arabidopsis - (plant) genetics.
mice - genetics and diseases.
drosophila (fruit fly) - genetics . cell cycle. and vision
rats - phsyiology
rabbits
monkeys - higher brain functions, late stage human disease models.
dogs (in the past, very rare today) physiology.