In simple diffusion, small molecules without charges such as oxygen and carbon dioxide flow through a plasma membrane without assistance and without expending energy. Other substances such as proteins<span>, glucose and charged particles called ions cannot pass through the selectively permeable membrane.</span>
<span>The statement that is true according to the law of conservation of energy is D. all of the above. Energy cannot be created, it already exists everywhere around us. Energy cannot be destroyed, as it will always be present in some form or another. Energy can be converted from one form to another, and thus it will always exist without being destroyed.Hope this helps. Let me know if you need additional help!</span>
<u>Answer:</u> The mass of methylene blue that must be weighed is 
<u>Explanation:</u>
To calculate the mass of solute, we use the equation used to calculate the molarity of solution:
We are given:
Molarity of solution = 
Molar mass of methylene blue = 319.85 g/mol
Volume of solution = 100.0 mL
Putting values in above equation, we get:
Hence, the mass of methylene blue that must be weighed is
One swimmer can cover 100 meters in 30 seconds.
