Final answer:
The main water source for land plants is soil, where they absorb water and nutrients through their roots. Elements can be categorized as metals, non-metals, transition metals, and inner transition metals based on their properties.
Step-by-step explanation:
The main water source for land plants is generally the soil. Plants absorb water through their roots, which are embedded in the soil. While rain is important as it provides water to the soil, it is the soil that stores this water and serves as the immediate source for the plant. Essential nutrients are also taken up by plants from the soil where they are dissolved in water.
Regarding the classification of elements, fluorine (F) is a non-metal, uranium (U) is an inner transition metal, and copper (Cu) is a transition metal. Similarly, lithium (Li) is a metal, argon (Ar) is a non-metal, americium (Am) is an inner transition metal, and iron (Fe) is a transition metal. Metals are known for their conductivity, ductility, and malleability.