Answer:
The oxygen O2, and the carbon dioxide (CO2) dissolved in water are very important to keep live in aquatic bodies.
Explanation:
Oxygen (O2) is an element found in nature usually as a gas in the air that we breathe. Oxygen is very important for aerobic organisms, including us, the humans. It can dissolve in water, and it is vital for the health of aquatic habitats. If we have low quantity of oxygen dissolve in water means that could be a pollution problem. Actually the oxygen level is an indicator to determine the water quality. In order to survive the aquatic biota (animals and plants) need certain quantity of oxygen. The oxygen dissolved in the water comes from the air, because of the wind, rain, waves, currents, and from aquatic plants like algae thanks to a process call photosynthesis.
Carbon Dioxide (CO2) is a chemical compound. This gas also is found in the air, and can be dissolved in water easier than oxygen. Aquatic plants needs CO2, to produce their own food during the photosynthesis process. It´s very important to have enough CO2, for the growth of aquatic plants. But if we have to much CO2 the fish will not have enough oxygen and could suffocate and die. Aquatic animals through respiration process produce CO2, it also can be obtained from fermentation, and from the burning of any substance that has carbon C.
If we want to preserve live in the aquatic bodies we must keep the balance between oxygen and carbon dioxide.
Answer: -
2.5 mL
Explanation: -
Volume of final solution = 10 mL
Strength of final solution = 10 mg / mL
Amount of drug required = Volume of final solution x strength of final solution
= 10 mL x 10 mg/ mL
= 100 mg.
Strength of supplied drug = 40mg/ mL
Volume of supplied drug required = 
= 2.5 mL
Thus to make 10 ml of a 10 mg/ml solution. 2.5 mL will be needed.
This is what I got hope this makes sense:There is 1 mol of Mg 2+ ions in one mole of MgCl2, we can get that from the formula.
Multiply 3.00 moles by 6.022x10^23 to get moles of MgCl2.
There are 6.022x10^23 ions in one mole of substance.
(3.00)(6.022x10^23)
=1.81x10^24 Mg 2+ ions
Hope it helps though
C. It show how many moles are used of each substance.
