Answer:
(2) Organelles must work together and their
activities must be coordinated
Explanation:
Organelles are usually located in cells. They are saddled with the role of performing specific functions in the cells for the overall functioning of life. In eukaryotic cells, the organelles are membrane bounded but in prokaryotic or primitive cells such is not the case.
Examples of cell organelles are ribosome, food vacuole, nucleus e.t.c. Just like organs in the body, organelles must work together in order to enhance life.
B- is the answer
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Answer: The given statement is true.
Explanation:
According to the Dalton's law, total pressure of a mixture of gases that do not react with each other is equal to the partial pressure exerted by each gas.
The relationship is as follows.

or, 
where,
....... = partial pressure of individual gases present in the mixture
Also, relation between partial pressure and mole fraction is as follows.

where,
= mole fraction
Thus, we can conclude that the statement Dalton's law of partial pressures states that the total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture, is true.
solution:
You need to find the frequency, and they have already given you the wavelength. And since you already know the speed of light, you can use formula (2) to answer this problem. Remember to convert the nano meters to meters because the speed of light is in meters. 
