Answer: Air pollution is responsible for seven million deaths each year in the US
Explanation: https://www.who.int/health-topics/air-pollution#:~:text=The%20combined%20effects%20of%20ambient,cancer%20and%20acute%20respiratory%20infections.
Umbilical cord and haploid
The scientist you're looking for is an anthropologist.
A, bacterial conjugation
Explanation:
I think it's this because in step 4, the things under the oval-ish circle looks like bacteria
Amphibians, birds, and mammals look the most similar as embryos.