I believe it should be A. The presence of a nucleus. Because for response B, it's not true as prokaryotes and eukaryotes possess cell membranes. It can't be C as their ability to interact with the environment is not as different. This is also true of ability to reproduce.
Answer:
There is a great difference between light and scanning electron microscope. The source of illumination is light rays in light microscope while in scanning electron microscope electrons are the source of illumination.
The resolving and magnification power of scanning electron microscope is much greater than that of a light microscope. The magnifying power of a light microscope is 1000X and of electron microscope is 10,00,000X.
In light microscope image is seen through the eyepiece while in scanning electron microscope it is seen on a fluorescent screen. Even small specimens up to 0.1 micrometers can be seen by scanning electron microscope which is not possible to see by light microscope.
Answer: Mg2+
Explanation: ATP(Adenosine triphosphate) is unstable in nature and also shows the property of being electronegative. It is seen that 
is the electronegative element and it is bonded with the Mg2+ being a positive divalent and thus achieve the stability and reducing the electrostatic repulsion.So, there is the combination between the negatively charged phosphate groups with the Mg2+. Therefore option (a) is the correct answer.
Answer:
D. IRIS
Explanation:
Generally in humans and also in most mammals and birds, the iris is a very small circular structure in the eye, responsible for controlling the diameter and size of the pupil and also with the amount of light reaching the retina.
finallly eye color is also known to be defined by that of the iris
Carbon dioxide and sunlight I think
