The correct answer is: A. How does changing the amount of water affect the growth of corn?
While options B, C & D are not impossible to test, option A is the only question that can be tested using quantitative methods, such as statistical analysis. The question in option A states: "How does changing the amount of water affect the growth of corn?". This question is easily testable using scientific investigation, because controlled or measured amounts of water can be added to corn, and the consequent growth rate of corn can be easily measured and recorded. However, the questions in options B, C & D cannot be precisely measured using quantitative tools, since they aim to measure qualitative (subjective) factors, such as: ethics, happiness and disappointment.
Answer:
The correct answer will be option-DNA polymerase can only add nucleotides to the free 3' end
Explanation:
DNA replication process produces the exact copy of DNA which requires various enzymes. The function of adding a nucleotide to the daughter strand is performed by the enzyme called DNA polymerase.
The DNA polymerase enzyme catalyses the process of DNA replication which requires energy provided by the dNTP. The enzyme adds new nucleotides at 3'-OH end of the DNA which favour the reaction energetically.
Thus, the new DNA strand appears to be elongated in the 5' to 3' direction.
C. Decreased death rate is the answer
The increase of carbon dioxide in the atmosphere creates a greenhouse effect.
To explain this usually some sunlight is reflected back into space while some is absorbed by the earth keeping the planet warm. However the increase in greenhouse gases such as carbon dioxide prevent the light from reflecting back into space and this light becomes trapped causing the earth to heat more then it should. You can almost think of the trapped heat from the greenhouse gases as a blanket around the earth trapping the heat in.