Yur answer is 8 hope it helped
        
             
        
        
        
Answer:
Nitrogen
Explanation:
It can change in the Atmosphere or on land:)!
 
        
             
        
        
        
Touching a hot pan and yanking your hand away--That is nervous system.
Going through puberty is controlled by the pituitary gland.
jumping up and down is controlled by the muscular system.
Breathing harder during a jog is controlled by the respiratory system.
Getting energy to sit through class by eating cereal and a banana is controlled by digestive system and muscular system.
hope it helps
        
             
        
        
        
Answer:
All errors described will result in a negative result 
Explanation:
The enzyme-linked immunosorbent assay (ELISA), is a test used to detect and measure antibodies, antigens and proteins in the blood. An ELISA test uses antibodies and/or antigens that are coupled to an easily-assayed enzyme, thereby this approach combines antibody specificity with the sensitivity of simple enzyme assays. ELISA test involves an antibody or antigen that reacts to form an antigen-antibody complex, where such reaction is interpreted as a positive result. The negative results are evidenced by the lack of reaction, which may be caused by some error during the chain of reactions in the ELISA test: antigen >> primary antibody (reaction) >> functional secondary antibody (reaction) >> conjugated enzyme (reaction) >> functional substrate.