The four limitations are
1.It's often impossible to repeat trials on the same subjects.
2-Subjects may report an inaccurate medical history.
3-It can be difficult to control all possible variables.
4-It's impossible to come up with testable scientific questions for human subjects.
Research involving human beings is ultimately necessary for improvements in human health and welfare. Any results about healthy physiology, illness causes, treatment effectiveness, learning, or behavior must be verified by carefully controlled investigations involving human participants. Sadly, not all human research have been valid and beneficial. It is possible to harm people in the name of research. The most well-known instances happened in Nazi Germany. Investigations conducted after the war found several crimes, including experiments in which participants were submerged in extremely cold water to determine how long it would take them to pass away from hypothermia.
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Answer:
Alligators: Growth depends greatly on the surrounding environment, including temperature, and sexual maturity is reached at approximately 6 feet long. The life span varies greatly for these large reptiles, averaging 35 to 50 years for wild alligators and 60 to 70 years for crocodiles.
Humans:In summary, the human life cycle has six main stages: foetus, baby, child, adolescent, adult and elderly. Although we describe the human life cycle in stages, people continually and gradually change from day to day throughout all of these stages.
Answer: The correct answer is option C. To form RNA molecules from DNA molecule.
Explanation:
The main function of transcription is to form ribonucleic acid (RNA) molecules from deoxyribonucleic acid (DNA) molecule present in the nucleus. In transcription, small part of DNA is copied and attached to the RNA molecule with the help of enzymes i. e. RNA polymerase.