Which characteristics are shared by birds and mammals?
they have a three-chambered heart and are endothermic.
they typically give birth to live young and fertilize internally.
they reproduce sexually and typically give birth to live young.
they are endothermic and reproduce sexually.

They are endothermic and reproduce sexually.

Explanation:

I did the unit test on edg. 2020

the "dirty dozen" chemicals banned in an international treaty are formally known as persistent organic pollutants, or pops. the united nations environment program provided this background on what they are and what they can do to humans and wildlife.

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he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?