Depends on the magnification you are looking for... usually, a light microscope is enough (1000x max magnification)...
An electron microscope is powered by high energy beams and can magnify many times higher than the light microscope (where magnification is limited by the wavelength of light). The magnification of an EM is on the nano scale.
(P.S.: as a chemist, I'd always choose an EM over an optical microscope as I can always zoom in or out depending on my needs) ;)
Viruses are actually smaller than bacteria but they're not bacteria. So D is wrong.
Viruses don't grow and aren't made of cells, and despite being able to reproduce, they're not living. So C is correct.
As for the other two, I'm not entirely sure what they mean but C is the answer.
Answer:
a. All of these
Explanation:
<em>The characteristic of skin that makes it unpleasant for most bacteria would be due to all of the conditions.</em>
Most bacteria require humid condition in order to grow and as such, the desiccated nature of the normal human skin makes it difficult for them to establish themselves and grow on it.
The pH of the skin is usually acidic due to the production of lactic acid during sweating and the activities of the normal skin bacteria. The acidic pH hinders the growth of bacteria that can potentially become pathogenic to the skin.
Also, the skin produce antimicrobial substances at low pH which hinders the growth of pathogenic bacteria.
Hence, options b, c, and d are correct.
Answer:
Yes, you are right, it is over three hundred (300) centimeters
