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.
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Explanation:
A university is building a new student center that is one third the distance from the arts center to the Academic.
The correct answer is D: I and II only.
Viruses have protein capsids, which protect their genetic material. This capsid sometimes is covered by viral envelopes which have glycoproteins on their surface. Glycoproteins help in the process of binding to the host cell and infecting it. In this example, virus III has the structure of a bacteriophage and it does not seem to have glycoproteins. Bacteriophages use their tail fibers to attach to the bacterial host and inject their genetic material. On the contrary, viruses I and II have glycoproteins sticking out of their envelopes.
Answer:
A) The radial orientation of cellulose microfibrils in the cell walls of guard cells causes them to bow outward and open when the stomatal pore when turgid.
Explanation:
Stomata are pores on the surface of leaves that work as valves controlling the gas exchange in plants; they are bordered by a pair of curved guarded cells in charge of opening and closing by increasing or decreasing the stomatal pore area.
Guard cells walls structure consist of a combination of stiff cellulose microfibrils oriented along the circumference of the cells and a softer matrix material which makes it possible for stomata pore to open by increasing water pressure (turgor).
Option B states that when guard cells become turgid, they close the stomata. This is a false statement as we explained before.
Option C states that light (known stimulant for opening stomata) causes guard cells to become flaccid which is also false. Guard cells become turgid in order to open the stomatal pore.
Option A is correct.
