<span>The study of the interactions between living things and their environment is called ecology.</span>
        
                    
             
        
        
        
Answer:
The electron transport chain is a cluster of proteins that transfer electrons through a membrane within mitochondria to form a gradient of protons that drives the creation of adenosine triphosphate (ATP). ATP is used by the cell as the energy for metabolic processes for cellular functions.
Explanation:
The electron transport chain is used to pump protons into the intermembrane space. This establishes a proton gradient, allowing protons to be pumped through ATP synthase in order to create ATP. This method of ATP production is called oxidative phosphorylation.
Resources: 
https://www.varsitytutors.com/high_school_biology-help/understanding-the-electron-transport-chain
https://biologydictionary.net/electron-transport-chain/
 
        
             
        
        
        
Answer:
1. Brain
2. Peripheral nerves
Explanation:
The nervous tissue or the nervous system is a system in the humans or animals formed by the neurons.
The nervous system can be categorised into two types based on the structure and functions: the peripheral nervous system and the central nervous system.
The central system of neurons comprises of the neurons present in the spinal cord and the brain and the peripheral system which comprises the nerves of the organs present except the brain and the spinal cord like the nerves in the limbs (legs, arms).
Thus, Brain and Peripheral nerves are correct.
 
        
             
        
        
        
They work like a lock and key. Each enzyme is designed to fit into a specific substrate. Well let me start by explaining what an enzyme is and then a subtrate. An enzyme is a protein that speeds up the chemical reaction in a living organism. An enzyme acts as a catalyst for specific chemical reactions, converting a specific set of reactants called substrates into specific products.