Answer:
D. "always" cover the microscope when not in use.
Explanation:
when you are finished using a light microscope or any microscope in general you always need to put the cover back on it. Mostly, to protect it from any harmful bacteria, light etc. and to keep it clean and, from collecting dust.
Answer:
Explanation:
Fundamental niche is the entire set of conditions under which an animal (population, species) can survive and reproduce itself. Realized niche is the set of conditions actually used by given animal (pop, species), after interactions with other species (predation and especially competition) have been taken into account
Answer:

Explanation:
The distance to the Sun is 5,890,000,000,000. We need to write this distance in km.
A number can be written as
in scientific notation where x is a real no and y is any integer.
There are 10 zeros in the given number and also there are 12 digits after. It would mean that,

So, the distance in scientific notation is : 