Answer:
Explanation:
This is a problem based on time dilation , a theory given by Albert Einstein .
The formula of time dilation is as follows .
t₁ = 
t is time measured on the earth and t₁ is time measured by man on ship .
A ) Given t = 20 years , t₁ = ? v = .4c

=1.09 x 20
t₁= 21.82 years
B ) Given t = 5 years , t₁ = ? v = .2c

=1.02 x 5
t₁= 5.1 years
C ) Given t = 10 years , t₁ = ? v = .8c

=1.67 x 10
t₁= 16.7 years
D ) Given t = 10 years , t₁ = ? v = .4c

=1.09 x 10
t₁= 10.9 years
E ) Given t = 20 years , t₁ = ? v = .8c

=1.67 x 20
t₁= 33.4 years
<h2>
Answer: Pulsars</h2>
A <u>pulsar</u> is a neutron star that emits very intense electromagnetic radiation at short and periodic intervals ( rotating really fast) due to its intense magnetic field that induces this emission.
Nevertheless, it is important to note that all pulsars are neutron stars, but not all neutron stars are pulsars.
Let's clarify:
A neutron star, is the name given to the remains of a supernova. In itself it is the result of the gravitational collapse of a massive supergiant star after exhausting the fuel in its core.
Neutron stars have a small size for their very high density and they rotate at a huge speed.
However, the way to know that a pulsar is a neutron star is because of its high rotating speed.
Answer:
Contemporary light microscopes are able to magnify objects up to about a thousand times. Since most cells are between 1 and 100 μm in diameter, they can be observed by light microscopy, as can some of the larger subcellular organelles, such as nuclei, chloroplasts, and mitochondria.
A cell is the smallest unit of a living thing. A living thing, whether made of one cell (like bacteria) or many cells (like a human), is called an organism. Thus, cells are the basic building blocks of all organisms.
Cells have many structures inside of them called organelles. These organelles are like the organs in a human and they help the cell stay alive. Each organelle has it's own specific function to help the cell survive. The nucleus of a eukaryotic cell directs the cell's activities and stores DNA.
If the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. When this happens, the cell must divide into smaller cells with favorable surface area/volume ratios, or cease to function.
Explanation: