The answer is negative controls. These are groups where no phenomenon is probable. They ensure that there is no effect when there should be no effect. Where there are only two possible outcomes, e.g. positive or negative, if the treatment group and the negative control both produce a negative result, it can be concluded that the treatment had no effect. If the negative control group and the treatment group both yield a positive result, it can be inferred that a puzzling variable is involved in the occurrence under study, and the positive results are not only due to the treatment. In other examples, outcomes might be measured as lengths, times, percentages, and so forth.
Answer:
Chromosomes are coiled structures made of DNA and proteins. They contain genes, which basically code for proteins. Chromosomes form after DNA replicates. In other words, chromosomes form as DNA becomes foiled during the process of prophase I, thus creating chromosomes.
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<span>The correct option is: IT HELPS CARRY AN IMPULSE BACK TO THE NEXT NEURON. There are two types of neurons, excitatory and inhibitoty neurons. Both serve to transmit impulse from one point to the other. Each neuron usually makes several connections with other cells.</span><span />
The ocean moderates the Earth's climate. Most solar radiation occurs at the Equator, whereas the poles receive little radiation. The ocean<span> transport warm water from the Equator toward the poles and cold water from the poles back to the Equator. The oceans provide a habitat for much of the marine life exploited by humans, such as harvested fish. The oceans act as a massive carbon sink, as phytoplankton absorb carbon from the atmosphere through photosynthesis. The ocean also provides a medium for large scale transportation of goods through shipping. It is unlikely that vehicles as large as container ships could ever be transported over land.</span>
