The correct answer is D.
<u>It is an observational study</u><u> because the researcher is </u><u>NOT</u><u> manipulating the explanatory variable</u>, whether a person drinks green tea or not, in order to study the effect of the value it takes, over the dependent variable: LDL cholesterol level.
<u>In opposition, experimental studies manipulate the explanatory variable</u> in order to assess the effects caused on the dependent variable by such deviance.
Answer:
falling on his head
Explanation:
it depends on how hard he hit it but yea
Answer:
D. Humankind spread to inhabit all parts of the globe.
Explanation:
Paleolithic humans were nomads, so they moved from place to place when they were running out of food. This led to a big spread of humankind from Africa to Eurasia, the Southeast region of Asia, and Australia. Afterward, they started inhabiting Europe to finally reach America from North to South.
I think the farmers because those dams are blocking the fertile soils from coming so he or she is stuck with what he or she has and buys so they have less fertile rich soil to help grow plants