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
 
        
             
        
        
        
On where mitochondria or chloroplast?
        
             
        
        
        
Answer:
genetic drift
Explanation:
Genetic drift is a change in the frequency of an allele within a population over time. There are no environmental influences that cause genetic drift to occur.
 
        
             
        
        
        
Answer:
Neutral
Explanation:
The charge of an oxygen atom is neutral.
 
        
             
        
        
        
Answer:
Either A or C but A is a bit more true
Explanation:
You can measure one on option C but you can measure both
on answer A. Hope this helps you out.