Which element is absorbed by mycorrhizal fungi?

Carnivorous plants like $Nepenthes$ and Venus fly trap have nutritional adaptations. Which nutrient do they especially obtain and from where?

In $Pinguicula$ (butterwort),leaves are large and fleshy and bear $2$ types of glands. These are:

Insectivorous plants usually grow in soils which are deficient in

Drosera catches insects by means of

Why is mycorrhiza considered a symbiotic association?