Answer:
Radiation is energy that comes from a source and travels through space at the speed of light. 
 
        
             
        
        
        
Answer:
True
Explanation:
A mole is defined as 6.02214076 × 1023 of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
 
        
                    
             
        
        
        
Answer:
A student practicing for the outdoor track team begins to sweat. To what stimulus is the body responding?
Explanation:
 
        
                    
             
        
        
        
The second one, b synthesis reaction
        
                    
             
        
        
        
K₃PO₄ → 3K⁺ (aq) + PO₄³⁻(aq) 
One mole of PO₄³⁻ ion gets dissociated from one mole of K₃PO₄ 
As per the definition of Avogadro's number, 1 mole = 6.022 x 10²³ ions
One mole of PO₄³⁻ ions x  (6.022 x 10²³ ions/ 1 mole of PO₄³⁻ ions ) 
= 6.022 x 10²³ ions 
Therefore , there are 6.022 x 10²³ PO₄³⁻ ions in a mole of K₃PO₄.