The four limitations are
1.It's often impossible to repeat trials on the same subjects.
2-Subjects may report an inaccurate medical history.
3-It can be difficult to control all possible variables.
4-It's impossible to come up with testable scientific questions for human subjects.
Research involving human beings is ultimately necessary for improvements in human health and welfare. Any results about healthy physiology, illness causes, treatment effectiveness, learning, or behavior must be verified by carefully controlled investigations involving human participants. Sadly, not all human research have been valid and beneficial. It is possible to harm people in the name of research. The most well-known instances happened in Nazi Germany. Investigations conducted after the war found several crimes, including experiments in which participants were submerged in extremely cold water to determine how long it would take them to pass away from hypothermia.
Learn more about Medical research here
brainly.com/question/15215894
#SPJ10
Answer:
The structure of the cell is very much linked with the functions of the cell.The cardiac muscle is made of myocardium which serves the body by providing the blood, nutrients and oxygen.The cardiac muscles appears stripped when seen under microscope.
The skin consists of the tissues and cells which are close enough to create a boundary which does not allows the entry of materials and pathogens inside the body.
Hence, the function and the morphology of the cells are somewhere related to each other.
Answer:
<em><u>Commensalism</u></em>=Birds that live among cattle to eat insects stirred up by grazing. it
<em><u>Commensalism</u></em>=An Egyptian plover eating bugs off of a giraffe or rhino.
<em><u>Parasitism</u></em>=A tick living on a dog drinking its blood
<em><u>Predation</u></em>=A bear catching and eating a salmon from a river.
<em><u>Predation</u></em>=A bobcat catching and eating a rabbit.
<em><u>Mutualism</u></em>=A clown fish living in the tentacles of an anemone protected from predators.
<em><u>Mutualism</u></em>=Bees gathering nectar and then spreading pollen from a flower.
<em>Parasitism</em>=A tapeworm living in the digestive system of a horse.
Xylem transports and stores water and water-soluble nutrients.
Phloem transports sugars, proteins, and other organic molecules.
You see first the light wave because light travels faster than sound. Hope this helps
