Some companies advertise and sell mycorrhizae to home gardeners and commercial farms, claiming that the presence of mycorrhizae improves plant growth and survival. If the company conducted experiments on plants with and without mycorrhizae, which of the following measurements would support their claim?
A) smaller apple size in plants with mycorrhizae than in plants without mycorrhizae
B) increased production of corn ears in plants with mycorrhizae than in plants without mycorrhizae
C) increased need for fertilizer in plants with mycorrhizae than in plants without mycorrhizae
D) increased mortality in plants with mycorrhizae than in plants without mycorrhizae

Growth is generally defined as an irreversible increase in the size, weight, height, etc. of organisms. Depending on the organism, growth can be measured in terms of dry weight, height, number of fruit, size of fruit, number and size of leaves, number of cells, etc.

Hence, option A is incorrect because smaller apple size in plants with mycorrhizae is an indication of negative effects of mycorrhizae on the growth of plants. Option C in also incorrect because increased need of fertilizer in plants with mycoorhizae means the organisms has negative effects on the growth of plant. Increased mortality as a result of mycorrhizae is also a negative relationship of mycorrhizae on growth.

Therefore, the only correct option is B. It indicates a positive relationship of mycorrhizae on growth of plant.