Therefore, in order to swim in the English channel, in which its waters are extremely cold, we need carbohydrates like glucose that provide 4 kilocalories per gram. ... Fats are much more energetic foods, producing about 9 kilocalories of energy per gram, more than double that of sugar. Experts recommend that no more than 30% of the calories in our diet come from fat.
They either get their source of nutrients from something else. Or, they could also have shorter roots so that they only reach the top of the soil. They probably won't need as much nutrients to survive either.
