Answer:
number 2 i think is the answer
Answer:
every one lays eggs. No bird gives birth to live young. Birds quickly form and lay an egg covered in a protective shell that is then incubated outside the body.
Birds developed much great mobility than a mammal, but at the cost of being unable to carry its growing offspring about in its body. Unlike, say, a dog carrying a litter of puppies.
Explanation:
