Answer:
D
Explanation:
it has to be D because its talking about "how does a volcanic ash affect water systems"
A physical change is change in shape, size, reversible, and change in matter
Answer:
Epidemologists.
Explanation:
Epidemologists are responisble for systematically ivestigating the distribution (frequency, patterns of who disease spread between) and determinants (causes, risk factors, pathogen) of health-related states and events in specified populations (neighborhood, school, city, state, country, global)."
