I think the top three statements are the answer.
Answer:
conducting research to observe things in their natural habitat.
Explanation:
for example if someone is studying a certain culture, they would study the peoples culture, folklore, ways of living, and would interview them.
<span>Earth consists of four major layers: the crust, mantle, outer core and inner core. While most of the layers are made of solid material, there are several pieces of evidence suggesting that the outer core is indeed liquid. Density, seismic-wave data and Earth’s magnetic field provide insight into not only the structure but also the composition of Earth’s core</span>
the anwser for your question: pH
<span>The answer is, C. Antibiotics are often ineffective in treating older people who have deficient immune systems
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