The correct answer is (B) Photosynthesis and diffusion from the air
Dissolved oxygen enters the water from photosynthesis and through air. The The aeration of water can be caused by wind. From the air oxygen diffuse into the water and gets mixed in the it through circulation. The oxygen is also produced as a waste product of photosynthesis from blue-green algae, phytoplankton, etc which is added in water.
Answer:
The companies take away the bottle as "security deposit and however they can recycle and reuse it."
Explanation:
When buying different beverages from a person distributing, a deposit needs typically to be paid to the distributor from the containers that have been taken. However, the distributor will issue a refund once the bottle that was taken has been returned to the place of purchase. Therefore, the distributor will reimburse the redemption of the retailer the amount that was deposited for every container. The additional handling fees usually added in some countries. The deposits that remain unredeemed are taken to the state or kept by distributors.
the answer to your question is the amount of time and the effect it has on each material as well as the fact that the nitrogen cannot change it is an unchangeable variable whereas everything else the time, the substance of the subject, the possible formation of nodules can change without changing the identity of the experiment itself otherwise, you have a dependent variable. I hope this helps :-)