Why does tying the arm above the elbow make veins in the forearm more visible?

Lab reagent, hypothesis test.a reference solution used as a lab reagent is purported to have a concentration of 5 mg/dl. six samples are taken from this solution and the following concentrations are recorded: (5.32, 4.88, 5.10, 4.73, 5.15, 4.75) mg/dl.these six measurements are assumed to be an srs of all possible measurements from solution.they are also assumed to have a standard deviation of 0.2, a normal distributin, and a mean concentration equal to the true concentration of the solution.carry out a significance test to determine whether these six measurements provide reliable evidence that the true concentration of the solution is actually not 5 mg/dl.

How many moles of oxygen react with 12 moles of aluminum

The primary products of complete combustion of fossil fuels are a. carbon dioxide and water b. methane and water c. carbon monoxide and water d. carbon dioxide and carbon monoxide