Culturing of plants in soil less medium is called hydroponics. Plants are raised in small tanks filled with a solution containing appropriate quantities of all mineral elements. The solution is changed from time to time. It has a mechanism for aeration and circulation. Iron is added as Fe-EDTA otherwise it gets precipitated. EDTA is a chelating agent which keeps the metal ion in the soluble state. There is no need of organic matter. Hydroponics is useful in areas having thin, infertile and dry soils. Through this technique out of season fruits and vegetables can also be grown. 

Thus the correct option is D.

The term hydroponics was coined by William Frederick Gericke.

Hydroponics is the art of growing plants in absence of soil in a nutrient medium of defined concentration. It was initiated by Von Sachs. The technique is useful because plants can be grown in a defined medium. Pests can be avoided and plants can be protected from floods and drought etc. Also plants can be protected from various soil and water pollutants. In future, when pressure on land increases due to population growth, hydroponics will emerge as highly useful technique.

• In 1860, Julius von Sachs, a prominent German botanist, demonstrated, for the first time, that plants could be grown to maturity in a defined nutrient solution in the complete absence of soil. This technique of growing plants in a nutrient solution is known as hydroponics.
• Hence Hydroponics is growing plants in a solution of mineral nutrients.
• So, the correct answer is 'Solution of mineral nutrients'.

Hydroponics requires less water than irrigation on agricultural lands.

Hydroponics is a technique of growing terrestrial plants.

Hydroponics requires 10 times less water than normal agricultural plants that require proper methods of watering. A lot of water gets evaporated from the soil or seeps deep inside the layers. But in hydroponics water requirement is just 1/10 of water requirements of traditional agriculture.

Growing medium is an important component of hydroponics.

Hydroponics was pioneered by Julius Von Sach. It is a technique of growing plants in aqueous solution of nutrients. It can be used to find out the essential nutrients for plants. This technique is also called soilless cultivation.

Hydroponics is the science of growing plants in a medium other than soil, using mixtures of the essential plant nutrient elements dissolved in water.
The first experiments was performed by Sachs in the year 1860. Later, Knop from 1861-5 performed experiments related to hydroponics. Both of them made synthetic solutions of essential plant nutrients in water. Included in these solutions were salts such as, potassium phosphate, calcium sulphate etc. giving the necessary elements N, P, S, Ca, Mg P and Fe. Mn were also included. 
Thus, the correct answer is option (A). 

Minerals are very important for plants because:

Ebb and Flow, or Flood and Drain is a system involves the periodic flooding and draining of the nutrient solutions. Basically, there are two phases of its operation. The Flood is when the water and nutrients flow the growing areas, flowing over the plants' roots. The drain is when the water drains back to the reservoir. These two actions take turn continuously, and hence their name.

So, the correct option is ‘it floods and drains periodically’.

Hydroponics is part of hydroculture and within this, the plant is growing in a soilless medium or in an aquatic-based environment, it uses only the mineral nutrient solution to feed the plants.

Hydroponics is a sub set of hydroculture. In this method plants are grown without soil by using nutrient solutions.

Solid medium culture is where plants or micro organisms are grown on a solid support like agar gel, etc.

The produce from hydroponics has longer shelf life as they are nutritionally superior to the normal plants. They are given nutrition directly into the solution and they hence direct all their energy into their growth and development instead of trying to find nutrients.

Culturing of plants in soil less medium is called hydroponics. Plants are raised in small tanks. They are filled with a solution containing appropriate quantities of all mineral elements. The solution is changed from time to time. It has a mechanism for aeration and circulation. Iron is added as Fe-EDTA otherwise it gets precipitated. EDTA is a chelating agent which keeps the metal ion in the soluble state. Hydroponics is useful in areas having thin, infertile and dry soils. Through this technique out of season fruits and vegetables can also be grown.

Growing plants in a nutrient solution in absence of soil is called hydroponics. This technique was pioneered by Julius Von Sachs. It is also called soilless cultivation.

Solution culture is being used for raising flowers and vegetables. This soil- less production of plants is called hydroponics. Plants are raised in small tanks. They are filled up with solution containing appropriate quantities of all mineral elements. The solution is changed from time to time.