They all have different compositions of protons, neutrons, and electrons. This causes variety and makes atoms different so they can make up different substances
        
                    
             
        
        
        
- B
Explanation:
Due to that is the answer to the question
 
        
             
        
        
        
Answer:
-blood type a
-blood type b
-SOMETIMES type o but very rarely.
Explanation:
Each biological parent donates one of their two ABO alleles to their child. A mother who is blood type O can only pass an O allele to her son or daughter. A father who is blood type AB could pass either an A or a B allele to his son or daughter. While a child could have the same blood type as one of his/her parents, it doesn't always happen that way. For example, parents with AB and O blood types can either have children with blood type A or blood type B.
 
        
             
        
        
        
Answer:
B (active transport using ATP)
Explanation:
Movement of substances normally occur in the direction of concentration gradient/difference i.e. the difference in concentration of a substance across a membrane. Letting molecules diffuse or pass down their concentration gradient does not require energy but pumping those molecules against gradient requires energy in form of Adenosine triphosphate (ATP). This process is called Active transport.
In order to perform certain cellular processes, cells need to move substances from their surroundings into the cell across their cell membrane. Moving this substances against the concentration gradient between the cell membrane and its extracellular fluid requires energy (ATP).
An example is the sodium-pottasium pump employed by animal cells in which they expend energy to move K+ molecules into the cell and Na+ molecules outside the cell against the concentration gradient of their cell membrane and extracellular solution.
 
        
             
        
        
        
Answer:
Aa
Explanation:
In Punnett Square, you are bringing the letters on the top to the numbered squares, if that makes sense. It is to predict the genotype of offspring.
So square 1, on the left is A, and on the top is A, so it would be AA. 
For square 2, on the left is a, and on the top is A, so it would be Aa.
For square 3, on the left is A, and on the top is A, so it is AA.
Square 4, your question, has a on the left, and A on the top, so it is Aa.
Hope it makes sense. You should probably watch a Punnett Square tutorial online or something for a full and more general explanation.