Answer:
Orbital period, T = 1.00074 years
Explanation:
It is given that,
Orbital radius of a solar system planet, 
The orbital period of the planet can be calculated using third law of Kepler's. It is as follows :

M is the mass of the sun

T = 31559467.6761 s
T = 1.00074 years
So, a solar-system planet that has an orbital radius of 4 AU would have an orbital period of about 1.00074 years.
Answer:
Light microscopes use light and glass objectives to illuminate and magnify objects
Explanation:
Light microscopes and electron microscopes are used to study cells. The electron microscope has many times more resolving power than the ordinary light microscope. A light microscope contains an objective lens and an eyepiece through which the final image is seen.
Both light and electron microscopes magnifies the image of the object. The magnifying power of an electron microscope is many times that of the light microscope.
I believe it would be magnet number four, this is because, with magnets, not people, opposites attract. Magnet 4 is the closest magnet to the large magnet with it's opposite facing the large magnet.
A. since the universe has no matter or energy on the outside