In a greenhouse, a plant would be best positioned so that it's exposure to sunlight would be a) within its optimal range. b) at its zone of stress. c) within its limits of tolerance. d) at the photosynthesis limit.

Option A.

Explanation:

A greenhouse is defined as a structure that contains walls and roof made up of  transparent material like glass or plastic, under which climatic condition is maintained for the regular growth of plants inside it.

In a greenhouse, best position for pant is maintained so that exposure of sunlight should be in its optimal range.

This is so because there must be adequate amount of sunlight falling on the plant for its proper growth and development because more or less than normal amount of sunlight is not good for plants.

Hence, a plant in greenhouse should be positioned so that it's exposure to sunlight would be  within its optimal range.

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .