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.
B PLANT<span> maximize its </span>photosynthesis
Sperm will not be able 2 leave his body
Hope it helps! :)
<span>There are three major groups of mammals, categorized on the basis of their method of reproduction. Monotremes lay eggs to have children instead of having the mother bear them. The second type of mammal is the marsupial, which are non-placental animals who carry their young in their pouches. Eutherians are the third group who are placental mammals.</span>
1. The energy left in the Quaternary consumer level is 0.06283 kcal.
2. 0.65 units of energy is still available at the tertiary consumer level.
<u>Explanation:</u>
Energy flow in an ecosystem obeys the ten percentage law According to which ten percentage of energy from a trophic level gets transferred to the next trophic level. In the given question plants belong to the trophic level , producers and it transfers 10 percentage of its energy to the primary consumer level.
In the question 1 the energy that the producers have is 628.3 kcal. Ten percentage of this i.e 62.83 kcal gets transferred to the primary consumer level. Ten percent of that which is 6.283 kcal gets transferred to the secondary consumer level. Ten percent of 6.283 kcal i.e 0.6283 kcal energy is transferred to the tertiary consumer level.
Thus the Quaternary consumer level gets ten percentage of 0.6283 kcal i.e 0.06283 kcal. In question B the initial energy at the primary level is 650 units. Ten percentage of 650 i.e 65 units reach the primary consumer level. Ten percentage of this 65 units then reaches the secondary consumer level. Thus the secondary consumer level has ten percent of 65 i.e 6.5 units of energy.
So the energy that reaches the tertiary consumer level is ten percentage of 6.5 i.e 0.65 units.