A scientist is evaluating the effectiveness of two new medicated ointments for skin rashes (Brand X and Brand Y). As a first step, the study tested the ointments on 21 patients with a chronic skin rash. Which scenario will tell the scientist more about the ointments? A Give 30 patients Brand X and 30 patients Brand Y, then after one week switch the medications for each group. B Give the 60 patients one brand, observe the results, and then give them the other brand
and observe the results. C Give 30 patients Brand X and 30 patients Brand Y. D Give 20 patients Brand X, 20 patients Brand Y, and 20 patients a cream containing no
medication.

During a fierce storm a large number of tall trees on an island are uprooted by the wind and die. most of the trees on the island are now short trees and produce seeds that grow into short trees. what concept is shown in this example? question 5 options: natural selection artificial selection genetic engineering gene splicing

Coral have a symbiotic relationship with what in order to eat?

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.