Answer:
i think it would be a but i am not 100% sure on that
When t=2, the ball has fallen d(2) = 16 (2²) = 64 feet .
When t=5, the ball has fallen d(5) = 16 (5²) = 400 feet .
Distance fallen from t=2 until t=5 is (400 - 64) = 336 feet.
Time period between t=2 until t=5 is (5 - 2) = 3 seconds.
Average speed of the ball from t=2 until t=5 is
(distance covered) / (time to cover the distance)
= 336 feet / 3 seconds = 112 feet per second.
That's what choice-C says.
Both cells are formed in bone marrow.....but t cells matures into thymus....and b cells matures into bone marrow ! both helps in defense !
B cells can connect to antigens right on the surface of the invading virus or bacteria.
T- cells can only connect to virus antigens on the outside of infected cells.
for more info , comment !