Answer:
Option-D
Explanation:
Casparian strips are the strips or band composed of a hydrophobic substance called the suberin which forms the ring-like structure in the endodermis of the vascular plants.
The Casparian strips are present around the vascular bundles in the endodermis to allow the uptake of the selective nutrients as the substance has to pass through the cell membrane before it enters the centre of the root or stele or vascular bundles.
The Casparian strips allow the movement of a substance through symplast mode only, therefore, is ensures the substance to pass through the cell membrane.
Thus, Option-D is correct.
 
        
             
        
        
        
The best question for this experiment is How does the composition of the soil affect the pH of the rainwater?.
<h3>What are the best factors being studied?</h3>
The main factors based on the description are:
- The pH of the rainwater: This is the factor manipulated by the researcher.
- The aluminum concentration: This is the factor researchers are evaluating.
<h3>What is the best question?</h3>
The best question would be one that relates the main two factors. Based on this, the best question would be: "How does the composition of the soil affect the pH of the rainwater?".
Learn more about rainwater in: brainly.com/question/14295571
 
        
             
        
        
        
Answer:
The given statement is true. 
Explanation:
Genome is not a steady entity, it is exposed to various kinds of heritable modifications, a sudden and heritable modification in the arrangement of the genome in an organism, which produces different forms of any gene is called mutation.  
The mutations provide the raw material for genetic evolution, mutation leads to the generation of alleles, in the absence of mutation all the genes would prevail only in one form, and the organism would lose to the tendency to evolve and amend with the changing environments.