Carbohydrates are the main energy source. But lipids are used for storing energy so
        
                    
             
        
        
        
Explanation:
1. Since the Lions are the predator and Gazelles are the prey therefore a predator-prey relationship exists between them. The predator-prey relation is also associated with the food chain in an ecosystem. If the number of prey is reduced then there are chances that the number of a predator will also be reduced but
2. The Lion is not just the predator of Gazelle but other animals also like deer therefore they can shift their resource of food from gazelles to another organism.
3.The change of the ecosystem will change the population of the predator as the population are adapted to grow in a particular ecosystem and change of population could reduce the population of a predator.
 
        
             
        
        
        
<h2>Exhaustion stage of general adaptation.</h2>
Explanation:
The final stage of general adaptation theory is known as exhaustion stage.
The general adaptation is  has been divided into three stages- Alarm stage, resistance stage and exhaustion stage.
The theory of adaptation describes the physiological changes that an organism undergoes when it is exposed to stress. 
The first stage,which is the alarm stage which is characterized by the burst of energy and the stressor acts as a stimulus.
The second stage is the resistance stage when the organism develops the resistance against  stressor.
The last stage is the exhaustion stage when the energy is sufficiently depleted and the final adjustment is attained.
 
 
        
        
        
Default network
When the brain is unoccupied, an fMRI indicates that blood continues to flow via a web of brain regions called the default network.
The default network is a web of brain regions that have activity that corresponds greatly with each other and different from other networks within the brain. The default network is active when an individual's attention is not concentrated on the external environment and it is measured with the functional magnetic resonance imaging technique (fMRI).