Two species of flies,  drosophila melanogaster  and  drosophila simulans, can mate. they usually do not mate, however, even if they are kept together in a laboratory. males court the females of both species, but the females prefer to mate with males of their own species. which isolating mechanism does this describe?
behavioral
temporal
artificial
anatomical

Researchers randomly divide participants into groups. each group takes a different amount of omega-3 fatty acid supplements daily for a month. one group receives a placebo. the researchers measure the impact on cholesterol levels in the blood. what is the purpose of random assignment in this experiment? a, to produce treatment groups with similar characteristics b, to ensure that all people with high cholesterol have an equal chance of being selected for the study c, to increase the accuracy of the research results and prevent skewness in the data

Write a paragraph at least 5 sentences “why all vaccinations should be mandatory”

What sentence best supports the statement that hormones are involved in the regulation of homeostasis? a. the hormone erythropoeitin increases the production of red blood cells when oxygen levels are low. b. the hormone oxytocin promotes labor contractions of the uterus during childbirth. c. the hormone melatonin induces sleep and its production is slowed by exposure to light. d. the hormone cortisol suppresses the immune system and is produced when the body is under stress.