That's a question that still remain a mystery in some areas on Earth. We all know that the animals that bear eggs are called "oviparous". They lay egg like a chicken. Reptiles do lay eggs also.
So here is the question: "Which one came first: the egg or the chicken?"
Solution
The Earth's history is divided in periods. In the jurassic period, the dinosaurs existed. They were reptiles which mean they had lain eggs before. If dinosaurs existed before chickens, maybe we cannot see a chicken around because they might have been eaten if they exist together with the dinosaurs.
So when the creataceous period came, the dinosaurs died and some birds existed. The chickens are part of these birds that bloomed into existence when the big reptiles were wiped out.
Have you seen the answer? The first that came into existence is egg. Because dinosaurs had lain eggs before these chickens existed.
Animals that bear eggs? Bears don't lay eggs silly-head. Do your research! Bears clone themselves in underground bear labs, which is one reason that I find them so terrifying.
I didn't say "bears lay egg". But I said:
Bear /verb/
-to give birth
it's a chicken because God made everything that can multiply the world hahaha.