Option C would be correct. The organ system can plays many parts at one time. Also, it is the only system listed.
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Correct answer choice is:
<h2>C. The question can be tested by a systematic procedure.</h2><h3>Explanation:</h3>
A scientific question is a problem that may point to a hypothesis and support us in solving the cause for any research. A good scientific question has several aspects. It should have any true results, should be testable.
A systematic process is usually intimately connected with the decisive study. In common, the purpose of a systematic process is viewed as a mechanism of control directed at decreasing the number and austerity of errors, omissions, and failures due to both human or technological functions associated.
The answer is (A) as <span> increasing risk of lung cancer is from increasing levels of exposure to outdoor air pollution and </span>particulate matter
RNA is an abbreviated form for Ribonucleic Acid. RNA is a nucleic acid that is present in the cells of all living things. Its primary function is to carry genetic instructions from DNA to ribosomes for the synthesis of proteins. There are three different types of RNA, these are messenger RNA, ribosomal RNA and transfer RNA. Ribosomal RNA are transcribed in the nucleus and the are the RNA components of the ribosomes.
The early hominid stages can be differentiated from one another based on the complexity of the tools used by these species. The tool evolved along with the evolution of the humans. The more the hominids evolved by more complex their tools became. The tools made by the earliest hominids were used to fish out the termites. These tool developed and became more widely used as the humans evolved.
Hence, the answer is 'by observing the complexity of the tools'.