Answer:
Major histocompatibility complex (MHC) antigens
Explanation:
The process in which recipient body rejects the transplanted organ is called a allograft rejection or transplantation rejection.
A transplanted organ contains Major histocompatibility complex (MHC) antigens which are required to be accepted by the recipient's body to function properly but T cells in recipient's body become alloreactive and recognize MHC antigens (donor-derived antigens) as foreign and starts making antibodies against it. Which means the recipient's body is rejecting the  transplanted organ.
Hence, the correct answer is "Major histocompatibility complex (MHC) antigens".
 
        
             
        
        
        
Answer:
A
Explanation:
The correct option would be A.
<em>According to the base-pairing rule, Adenine (A) always pairs with Thymine (T) (or Uracil in the case of RNA) while Guanine (G) always pairs with Cytosine (C).</em>
Hence;
              A-U
             G-C
             A-U
             A-U
             C-G
             T-A
Therefore, AGAACT would be transcribed to UCUUGA.
 
        
             
        
        
        
Explanation:
plants > herbivorous insects > predaceous insects > toads.
 
        
             
        
        
        
The sun is the ultimate source of energy and the process is Photosynthesis.
        
             
        
        
        
Answer: C) They can contain contaminants that can enter the air during storms or high winds.
Explanation: A is wrong because I got it wrong (Sorry, can't give much explanation there).
B is wrong because water contamination does not directly relate to respiratory health.
D is wrong because fertilizers can impact respiratory health (Explanation seems lack-luster, but I feel like this is common sense).
Hope this helps :)