Yes. They are too small to be seen with even the best optical microscopes.
No.
None can. They have to be seen using a electron microscope.
Viruses can only be seen with electron microscopes
SARS is a virus, requiring an electron microscope to be seen.
only under an electron microscope wiki it
The electron microscope is used to view things such as viruses as they are to small to be seen on a light microscope
Since a virus is far smaller than a typical cell (much smaller than a prokaryote) a virus cannot be seen by a regular microscope. To see a virus, you should get an electron microscope.
As viruses cannot be seen with the optical microscope, electron microscopes are used. All the "lenses" in an electron microscope are magnetic fields produced by electromagnets and/or electrostatic fields produced by electrically charged metal plates and/or rings.
AIDS is the disease caused by the virus called HIV. It can not be seen under a light microscope (as one in the class lab) but you must use an electron microscope as they are very tiny.
Hey this is a different question ummm...
Viruses are incredibly small - much smaller than the smallest of bacteria, even though many millions of bacteria could fit on a pinhead. Therefore viruses can only be seen with the help of a very powerful microscope such as a scanning ellectron microscope.
Because of their very small size Viruses can only be seen via an electron microscope.
A virus is the smallest because you can see a freckle with naked eye and you can see a skin cell under ordinary light microcope but viruses are ultramicroscopic and cannot be seen under light microcope. Instead a virus can only be seen under high resolution electron microscope.