Question

1. what is made possible by a high concentration of auxins in a plants shoot and root tips?

gravitropism
phototropism
thigmotropism
hydrotropi

Explanation:

Auxins are plant hormones. Gravitropism (also known as geotropism) is the growth of plants in response to gravity. In roots, a high concentration of auxin inhibits cell elongation, causing roots to grow downward. In shoots, a high concentration of auxin promotes cell elongation, causing shoots to grow upward. Phototropism is response to light, thigmotropism to touch, and hydrotropism to water.

Answer:

gravitropism