A cop car’s siren has a frequency of 700. Hz. If you are standing on the sidewalk as the cop car approaches you at a speed of 15.0 m/s, what frequency would you hear? The speed of sound is 343 m/s.

Answermuscle strength;

Phagocytes contain digestive enzymes to facilitate the process of phagocytosis

The answer to the question is (a)   

The cell reaction uses external supplies of a full and an oxidant, which are consumed and needs to be provided continuously. the cell will continue to provide electrical energy so long as there is a supply of fuel and oxidant.  hope this ! (: