Which of the following identifies the most important reason why the percentage of deaths due to infectious diseases dropped from 1970 to 2015?
Group of answer choices

A. The number of people living in poverty fell as nations became increasingly more developed.

B. More people moved into urban areas, and fewer people remained in disease-prone rural areas.

C. More children were immunized against the major infectious diseases.

D. The use of pesticides became increasingly effective at killing biological threats.

When does dna replication(make a copy of itself)?

Variety of living organisms; includes genetic, species, and ecological types.

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.