1) Arithmetic density- the number of people per square unit of land 
2) Physiologic density-  Is the number of people per square unit of farmland.
3) Agricultural density- is the number farmers per unit of farmland.
        
             
        
        
        
  Skin cells are made of proteins, water, and fat. But brain cells are only made up of amino acids, which ca make protein.<span />
        
             
        
        
        
3A- Negative feedback occurs when some function of the output of a system, process, or mechanism is fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances.
3B- Negative feedback loops are used to maintain homeostasis and achieve the set point within a system. Negative feedback loops are characterized by their ability to either increase or decrease a stimulus, inhibiting the ability of the stimulus to continue as it did prior to sensing of the receptor.
Hope I’ve helped ;)
        
             
        
        
        
Answer:
The correct answer will be options
1. Process includes glycolysis.
2. Between 2 and 38 ATP are produced per molecule of glucose input .
3. Much or most of the ATP produced is produced by oxidative phosphorylation.
4. Process involves electron transport and chemiosmosis.
5.  End products are CO₂ and H₂O.
6. Process involves the Krebs cycle.
Explanation:
Cellular respiration is the oxidative process which involves the breakdown of food molecules like glucose, amino acids and fats to release heat and energy in the form of ATP.
In the presence of oxygen or aerobic respiration it undergoes four stages: glycolysis, link reaction, Krebs cycle and electron transport chain while in the anaerobic reaction it produces ethanol and carbon dioxide by the process of fermentation.
Each stage produces energy in the form of ATP molecules or co-enzymes NADH OR FADH₂ like glycolysis produces 2 ATP and link reaction, Krebs cycle produces NADH OR FADH₂ in addition to ATP. Each NADH produces 3 ATP while Each FADH₂ produces 2 ATP during electron transport chain.  So, ATP molecules are produced between 2 to 38 ATP molecules in each stage with large number during electron transport chain from these co-enzymes.
The waste products produced in the stages of cellular respiration are CO₂ molecules and H₂O which is also known as metabolic water.