Which of the following scenarios is most appropriate for using a paired t-test (instead of an unpaired t-test)?

Suppose we have the counts of A, T, C, G in chromosome 1 of some individual. Denote them by  nA, nT, nC, nG.  Our goal is to check whether the A-T and C-G base pairing rule exists in human genome by hypothesis testing. Which of the following is the best choice for the test statistic? (Note that |x| denotes the absolute value of x.)

Consider the previous question. Which statement below is correct? 

In your own words explain how antibiotic resistance bacteria are formed?

The ability to sense changes in the environment and respond to them is called ________.

We measure the change in blood pressure of some hypertension patients after taking a new medicine. We conduct a hypothesis testing with null hypothesis being that the medicine cannot reduce blood pressure. We get the p-value from the test. Which statement is true? 

Consider the probabilistic modeling for following four data sets. For which data set would a mixture model be most appropriate?

Describe structure of water. Explain its polar nature and presence of hydrogen bond. Explain any four properties of water, how it is significant for living things and why water shows these unique properties?

What is the function of the serous membranes?

When an x-ray photon strikes an object, which of the following can occur?