<span>The election of President Obama is a significant event in American History due to the fact that he is the first African American President. The rise of ISIS is also another event that caused many events to transpire in recent history.</span>
Answer:
d. cross-sectional study
Explanation:
In research, a cross-sectional study consists of a gathering of data from a population or a subset of the population we want to investigate at an specific point of time. In other words, the data will give us an idea of what's happening within a group in a particular moment in time.
In this example, the researcher gives 20-year-olds, 40-year-olds, and 60-year-olds a questionnaire. He wants to know if older people are calmer than younger ones. We can see that <u>he wants to know what's happening within this groups (the 20 year-olds, the 40's and the 60's) during this particular time of their life </u>and therefore determine if the 60 year-olds are calmer. Therefore this is an example of cross-sectional study.
Answer: A large amount of energy is lost at each level, so there has to be a limit on the number of trophic levels.
Explanation:
Answer: Reducing the use of forest resources can enable humans to make it last longer.
Explanation: A reduction of the use of forest resources can help with the mitigation process. Mitigation can be defined as the reduction of the loss during any natural disaster. Forest is a rich source of oxygen, so we have to be very careful about the conservation of forest resources. It also serves numerous others functions like it can be use as shelter for different animals and birds. We have to minimize the uses of forest products.
Billy's condition is the result of:
- a disruption in his myelin sheaths.
<h3>
Multiple sclerosis</h3>
This disease of the nervous system ocurrs when the <u>myelin sheaths</u> are affected, in this affects the brain and the spinal cord, slowing down the signals obtained by the brain and the answers of this.
Multiple sclerosis can cause coordination and balance problems, in the same form that muscular weakness, by this reason, Billy has troubles walking and running.
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