Answer:
To check if it's properly cleaned.
Explanation:
When you finish using a microscope, you have to take out all your samples you were using and make sure it is completely clean so that no further contamination affects future sample analysis.
Also when you begin to use it, make sure it is clean so that when you analyze your sample(s) are free from other unexpected agents.
Answer : The answer is,
Explanation :
Scientific notation : It is defined as the way or representation of expressing the number that are too big or too small that is written in the decimal form. That means always written in the power of 10 form.
For example : 8000 is written as,
in this notation, the significant figure is, 1 but
in this notation, the significant figures are, 2
The given problem are :

According to the divide and multiplication rules of scientific figures, the final answer is only as precise as the value with the least number of significant figures.
Hence, the answer is,
Answer: They use other organisms for energy
Explanation:
Answer:
The player ran 91.44m.
Explanation:
The problem gives you the total distance between goal line to goal line in feet, and the answer must be given in meters, so you should convert the distance the player run from ft to m, because the player run the same distance from goal line to goal line to scores the touchdown.
So, you should apply the following conversion factor:

The player ran 91.44m.
Answer: its a single replacement reaction