Answer: d. none of the other answers
Explanation:
Enzymes that turn chemical energy into mechanical work are molecular motors.
There are three main components of cytoskeleton including microtubules, actin filaments and Intermediate filaments. Only actin filaments and microtubules carry the motor-driven transport on the cytoskeleton.
The most important feature of intermediate filaments is to provide the plasma membrane with mechanical support where it comes into contact with the extracellular matrix and other cells.
Unlike microtubules and microfilament , intermediate filaments are not involved in motility of the cells, hence do not associat with molecular motors.
Hence, the correct option is d.
<span><span>Fluency
disorder
</span>Fluency
disorder is a communication disorder that involves discontinuous flow and
timing of speech. It is mostly seen in children who are learning to speak. Physical
tension, negative reactions, and avoiding of speaking situations work together
with this disorder. Individuals with this disorder display repetition of words,
sound extensions and long pauses when speaking. For the question given above, a
12-year-old student who says "i-i-i-i want i-i-i-ice c-c-c-cream" is
exhibiting fluency disorder.</span>
<span>You can tailor the URL for each Sitelink Extension</span>
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.
Although most absorbed glucose is used to make energy, some glucose is converted to ribose and deoxyribose, which are essential building blocks of important macromolecules, such as RNA, DNA, and ATP.