Answer: Answer below
Explanation: pH is a measure  of the acidity or alkalinity of a solution. What the pH scale measures is basically the concentration of hydrogen and hydroxyl atoms in a solution. So, the last option is the answer. Another thing to keep in mind is solutions with a pH under 7 are acidic, solutions with a pH of 7 are neutral, and solutions with a pH over 7 are alkaline or considered a base. I hope this helped! Good luck:) 
 
        
             
        
        
        
You'r <span> Hypothalamus partially controls your hunger!
Happy to assist!</span>
        
             
        
        
        
Answer:
I would write "terrestrial/lives on land during all life stages" between the frog and pigeon branches.
Explanation:
Jaw evolution has started with fish, so i'd place that before the perch, evolution of four limbs is next and I would plate it between the perch and the frog. Evolution of an egg has ensured that organisms remain terrestrial during all stages of life and don't need to rely on water to lay their eggs. So I would place that between the frog and the pigeon. True mammary glands and true hair, as we know it formed on mammals so i'd place that between the pigeon and the rats (although synapsids evolved similar structures long before birds even existed). And lastly, I would place "walking on two legs" between rats and human branches. Because our ancestors evolved bipedalism relatively late. 
 
        
             
        
        
        
Answer:
there would be less jackrabbits, more sagebrus, and the coyotes would have less food leading them to death
Explanation:
what i said
 
        
             
        
        
        
They produce heat inside the core, creating a steam like substance (carbon dioxide)