Planet x is a terrestrial planet in our solar system. it has 21% oxygen in its atmosphere. humans can walk on this planet without the aid of a space suit. based on the description, planet x is

Your friend offers to show you an intrusive igneous rock. which of the following would you expect to see?

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.

Who discovered a pattern to the elements in 1869?