Physical barriers that help prevent an individual from contracting diseases include . A. White blood cells, enzymes, tears, and skin B. Sweat, stomach acid, skin, and enzymes C. Sweat, tears, skin, and mucus membranes D. Enzymes, mucus membranes, stomach acid, and tears Please select the best answer from the choices provided. A B C D.

answer;

18.5 seconds

explanation;

velocity is distance covered per unit time; it is given by displacement divided by time.

thus; time = displacement/velocity

total time = total displacement/velocity

total distance = 5000 meters south

total time = 5000/4.5

                  = 1111.11 seconds

but; 1 minute = 60 sec

thus; 1111.11 /60

                = 18.51 seconds

thus; the time taken is 18.5 seconds