I would say burning and combustion of fuels. hopefully that helps you.
Growing up? usually starts in 6th grade
1.firefighter 2.plumber 3. Electrician
4. Gardner 5.welder 6.pipe fitter 7.Mason
8. Fencer 9.blacksmith 10. Makeup artist 11.seamstress 12.painter 13.drafter 14.surveyor
15.butcher 16. Pastry chef
The answer for this question can find it on YT;
Explanation
The answer to your question is D. <span>. to protect students who cannot be vaccinated with herd immunity</span>