The term 'THEY SUPPORT PLANTS' can be broken down into two crossword solutions: STEMS (5 letters). Stems are an important part of a plant's anatomy, providing support and structure to the plant. They also transport water and nutrients from the roots to the leaves, and provide a pathway for the exchange of gases between the leaves and the atmosphere. Stems also play a role in the reproduction of plants, as they are the site of flower and fruit production.