The right answer is D (less responsive to antigens)
It is proven that, after puberty, thymus activity (an organ that is included in the lymphatic system, producing T cells that pick up antigens) decreases and that in adult and aged people the thymus has no role. Work done in humans indicate that in fact the cellularity begins to decline from birth in favor of lymphocyte perivascular spaces and connective and adipose tissue, which leads to a decrease in the capture of antigens.
Answer:
Solution
For figure (a)
During interval AB Velocity is +ve, so the particle is moving in +ve direction, but it is slowing down as acceleration (slope of v-7 curve) is negative.
During interval BC Particle remains at rest as the velocity is zero. Acceleration is also zero.
During interval CD Velocity is -ve, so the particle is moving in -ve direction and is speeding up as acceleration is also negative.
For figure (b),
During interval AB Particle is moving in +ve direction with constant velocity and acceleration is zero.
During interval BC Particle is moving in +ve direction as velocity is +ve, but it slows down until it comes to rest as acceleration is negative.
During interval CD Velocity is -ve so the particle is moving in -ve direction and is speeding up as acceleration is also negatived
A. Amber, because in the Prehistoric times the insects and small dinosaurs fell into amber and became preserved in the hardened sap.
