Answer:
D. There is no enough oxygen in the culture fluid
Explanation:
The cells in the test tube need to carryout one of the important metabolic processes of living organisms - respiration. The process involves the breakdown of glucose to generate energy for other metabolic processes in the cell.
Respiration can be carried out in the presence of oxygen (aerobic) or in the absence of oxygen (anaerobic). Human cells are primarily aerobic but can carryout respiration anaerobically in the presence of inadequate oxygen.
For aerobic respiration, glucose is broken down in the presence of oxygen to produce carbon-dioxide, water and energy in the form of ATP:

<em>In the absence of oxygen, the glucose becomes converted to lactic acid and a smaller amount of ATP is produced as compared to aerobic respiration.</em>
<em>Hence, lactic acid gradually builds up in the absence of oxygen due to anaerobic respiration.</em>
The correct option is D.
Answer: Your answer is indeed <u>A. Fair treatment.</u>
Hope this helps!
Answer:
The answer is:
B. Worms consuming the blood from mammals.
Algae isn't causing any harm to the sloth, rather its providing it with camouflage to hide from predators. Both creatures benefits since the algae gets to eat any parasites and other things in the sloths fur, plus they get a free ride and home in the process. The sloth isn't harmed and is helped by the algae since it provides camouflage (mutualism).
Tree frogs aren't causing harm to the trees since they are only using them to hide from predators, the tree serves as protection for the frogs and aren't harmed in the process (commensalism).
Two fish protecting each other from predators aren't harming each other in any way, rather they are protecting each other from another animal that wants to eat them (mutualism).
The worms however are harming the mammals because they are consuming the mammals blood, this is parasitism since one animal is benefiting and the other is harmed.
Hope this helps! :)
Electron shell is the outer orbital, while the inner orbital are just called orbitals.