Final answer:
The best choice of experimental tissue for evaluating the effects of growth factors on plant differentiation is the apical meristem, as it differentiates into various types of tissues and is responsible for primary growth.
Step-by-step explanation:
A researcher intending to test the effects of growth factors on the differentiation of plant tissue would find that the best choice of experimental tissue is b) Apical meristem. The apical meristem is involved in the primary growth of the plant, contributing to the lengthening of the plant structure. Apical meristems differentiate into protoderm, ground meristem, and procambium, which in turn give rise to the epidermis, ground tissue, and the vascular tissues (xylem and phloem), respectively.
The vacular cambium is part of the secondary growth, responsible for increasing the girth of the plant. While parenchyma cells are a type of simple tissue that makes up most of the inside of a plant and could potentially be used, the apical meristem is where active differentiation occurs, making it the most suitable for studying the effects of growth factors. The epidermal cells primarily serve as a protective layer and are less involved in differentiation.