Why does chickens lay eggs and humans give birth ?

Question

Why does chickens lay eggs and humans give birth ?

Answer 1

I think.......

chickens are birds while humans are mammals & also improved......

& so that the egg of chiken gets matured after coming out of the ovary.... Human also have egg...... but it  turned into fitus & then to a baby.

The process takes time & for that human have to remain pregnant for a longer time than chikens!!

Answer 2

Birds (chicken) - eggs

Mammals (human) - baby

Only mammals that lay eggs are the platypus and the echidna

It is better for birds to lay eggs while it is better for humans to have live young.

Answer 3

One possible reason for birds retaining egg laying and not evolving live births is to do with weight. A heavily pregnant bird would not be able to fly. It would therefore not be able to effectively search for food or escape predators.

Yes, I know chickens don't fly well, but their recent ancestors did.

Answer 4

Chicken's like Amphibian's lay egg's. We (Mammal's) give birth to live off spring because we are all way's under threat of predator's therefore we need to give birth to live young so they can try and get away. This goes back to when we lived in cave's.

Answer 5

chickens are birds while humans are mammals

Answer 6

Its the way God planned it.

Answer 7

It is evolution Birds are laying eggs and human who are mammals give birth

Answer 8

Well, humans are mammals.

Anything else that lays eggs isnt a mammal.

Answer 9

chickens are birds and humans are mammals.