Soilless culture helps in knowing:

Carefully observe the following figure.
$(a)$ Name the technique shown in the figure and the scientist who demonstrated this technique for the first time.
$(b)$ Name at least three plants for which this technique can be employed for their commercial production.
$(c)$ What is the significance of the aerating tube and feeding funnel in this setup?

The nutrient solution in flowering culture hydroponics:

Who demonstrated that plants could be grown to maturity in a defined nutrient solution in the absence of soil?

Name the technique used by researchers to explore plant nutrient deficiencies.

The technique of growing plants to maturity in a defined nutrient solution in the complete absence of soil is known as.............