Answer:
Plants and trees are the primary sources of food for a food chain or a food web. If the population of the primary producers reduces than it affects the whole food web. If the deciduous trees are destroyed due to a fire, there will be less food available for the primary predators. As a result, competition will begin between them and their population will decline. Due to this, the population of other organisms which fed on the primary consumers will also decline. 
 
        
             
        
        
        
Answer:
True. You can get vitamin A as "preformed vitamin A" which is already active and/or you can get vitamin A as carotenoids which the body can turn into active vitamin A.
Explanation:
There are two different types of vitamin A that can be obtained from food:
1.  Preformed vitamin A, which is already active, is found in animal products such as beef, fish, poultry and dairy products. 
2. Provitamin A, which is the inactive form, is found in plant-based foods, such as fruits and vegetables. The most common type of provitamin A is β-carotene, which is a carotenoid that the body can turn into active vitamin A via an enzyme named β-carotene 15,15'-monooxygenase.
 
        
             
        
        
        
Answer:
At 0 years, an event took place which is known as metamorphosis of igneous rock i.e., formation of igneous rocks from melted magma.
Strontium-90 is a radioactive element which undergoes beta decay to form yttrium-90. It has a half life of approximately 28 years and decay energy of 0.546 MeV. This radioactivity is used by geologist to estimate the age of the rock, fossils, meteorites etc. Other radioactive elements used by the geologists are carbon-40, potassium-40 etc.
Radiometric clock is set when the rock was formed in the past i.e., the moment when an ingenious rock was solidified from molten magma. 
 
        
                    
             
        
        
        
It will not capture modulated radio waves
        
                    
             
        
        
        
The least important role of nutrition in wellness is learning to <span>eat a high fiber diet. The other choices is important because a person should know the right diet he or she can take up. Learning to eat a high fiber diet is to specific and it is least important because you can have the right nutrition with the use of other vitamins and minerals also.</span>