Christopher wants to grow pineapples but doesn't have enough arable land. Therefore, he decides to grow pineapples with their roots in mineral-nutrient solutions or in inert mediums such as gravel, minerals, and wood. Which technology is he using

He is using Hydroponics.

Explanation:

It is hydroponics because

Hydroponics is an horticultural method of cultivating plants or growing plants without soil but by using water and nutrients or minerals solutions to cultivate the plants.

Hydroponics plants or herbs are cultivated inside a growing media and necessary nutrients, oxygen and water are supplied to boost their growths.

Examples of plants cultivated using hydroponics are tomatoes, lettuce, spinach, spring onions, blueberries e.t.c.