I think the correct answer from the choices listed above is option C. Cells in multicellular organisms differentiate as they continue to divide and increase in size because cells will now perform special functions and have become different to other cells. Hope this answers the question.
        
                    
             
        
        
        
The presence of a membrane bound nucleus describes the evolution of eukaryotes from prokaryotic organisms. The endosymbiotic theory describes the same, the large cells engulfed the smaller ones, and the engulfed cells were not digested but started living in mutual cooperation with the engulfing cell. Mitochondria and chloroplast are thought to be the engulfed cell
 
        
             
        
        
        
 Description of  thigmotropism is given below.
Explanation:
1. Thigmotropism is a plant’s response to touch.It is a plant’s response to an external stimulus.It can occur quickly or slowly.Thigmotropism may involve the closing and opening of plant leaves.
2. Thigmonasty or thigmotropism can be define as the response of touch shown by the plants. Here, touch is the external stimulus. It can be define as the movement of the plant parts in response to the external stimulus that is contact or touch. It is also known as Haptotropism. The plant may change it's orientation, shape and size of the plant parts.
3,The thigmotropism can be positive or negative depending upon the visual response shown by the plants. The response shown by the plants is generally fast  but may be slow. This response is shown by the plants in cases of danger of herbivory.Some plants like Mimosa pudica or touch me not plant shows thigmotropism by closing their leaves on touch
 
        
             
        
        
        
Answer:
The correct answer is option C. "2+".
Explanation:
A common procedure to test for the presence of antigens is to perform an agglutination reaction by performing an antibody screen. In an agglutination reaction that is graded  2+ the red blood cells start to be broken and medium-sized agglutinates are formed. In this reaction no red blood cells are free, only agglutinates are seen at the bottom of the microtubes. The characteristics of the reaction herein described concur with an agglutination reaction that is graded  2+.