<span>When used in glaucoma, this drug blocks beta-1 and beta-2 adrenergic receptors resulting in decreased aqueous humor production: Timolol
Beta blocker is common medication in glaucoma, but many beta blocker is selective to beta-1 or beta-2. Nonselective beta blocker would be timolol.</span>
        
             
        
        
        
Answer:
Circulatory system remove waste from the cell and provide clean blood to the cell.
Explanation:
During cellular respiration, lungs inhale oxygen which stored in the alveoli. The red blood cells contains hemoglobin that carries deoxygenated blood containing carbondioxide from the cell in the veins to the heart and unload this carbondioxide gas in the alveoli of the lungs and load oxygenated blood having oxygen from the alveoli through capillaries in order to provide oxygen to the cells that is necessary for the survival of humans. Platelets are the type of cells that helps in blood clotting whereas white blood cells provides immunity against pathogens.
 
        
             
        
        
        
Answer:
The three principal shapes associated with epithelial cells are—squamous, cuboidal and columnar. Squamous epithelium has cells that are wider than their height (flat and scale-like).
but where is the options?
 
        
             
        
        
        
Explanation:
amphibians have smooth, sticky wet and highly porous skin to perform various functions. 
reptiles have a dry, hard and scaly skin, which guards them in harsh conditions.
amphibians lay their eggs in water and cover them with gel.
reptiles lay their eggs on land and have a hard protective shell.