NEET BIOLOGY

Detailed explanation-1: -Such environmental responses are exhibited as plasticity of growth and development, and different organs exhibit different responses to given environmental stimuli. For example, stems show negative gravitropism, whereas roots show positive gravitropism in general.

Detailed explanation-2: -Positive gravitropism occurs when roots grow into soil because they grow in the direction of gravity while negative gravitropism occurs when shoots grow up toward sunlight in the opposite direction of gravity.

Detailed explanation-3: -Charles Darwin was one of the first to scientifically document that roots show positive gravitropism and stems show negative gravitropism. That is, roots grow in the direction of gravitational pull (i.e., downward) and stems grow in the opposite direction (i.e., upwards).

Detailed explanation-4: -Plant stem grows upward opposite to the force of gravity. Hence, it exhibits negative geotropism.

Detailed explanation-5: -Plants have the ability to sense a change in the direction of gravity, which leads to the re-orientation of their growth direction, so-called gravitropism. In general, plant stems grow upward (negative gravitropism), whereas roots grow downward (positive gravitropism).