A The observed differences in plants height are due to genetics.
The option which would most likely result in the greatest decrease in the rate of a chemical reaction is adding an enzyme inhibitor to a reaction catalyzed by an enzyme.
Enzyme inhibitor is known for slowing down any processes, especially when it comes to chemical reactions, so I'd say A is the correct answer.
Explanation:
Root hairs are found in the plant it is a hair-like structure present on the surface of the root tip and Root hairs have large surface area that increase the absorption rate of water and minerals.
Water is absorbed by root hair cells through the process called Osmosis and Minerals ions is absorbed root hairs by the process called active transport.
The function of root hair is to collect the minerals and waters present in the soil and then transfer these nutrients and water through roots to different parts of the plant.