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.
Should there be answer choices that go with this question?
If not here is an answer that may help.
This is how the cycling between photosynthesis<span> and cellular respiration occurs: </span>in photosynthesis<span>, carbon dioxide and water, </span>in<span> the presence of light energy, are converted to make glucose and oxygen.</span>
Answer:
Cell membranes are semi-permeable, which works like a sieve that determines what enters and leaves the cells.
Explanation:
It is semi-permeable and it allows molecules to diffuse inside.
<em>Feel free to mark it as brainliest :P</em>
I'd say, ina general way, that the most imporant cells in defense against parasitic organisms are definitely white blood cels, the cells responsible for defeating antigens, pathogens and deseases.
Although these might be the most important ones in that specific task (defending against parasitic organisms), all the cells in the immune system, along with other non-cell things are important, since they all play a specific role indispensable in our immune system.
Hope it helped,
BioTeacher101
When assessing the heart rate of a 6-month-old infant, you should palpate the brachial or femoral pulse