The xylem generally transports whereas the phloem transports

The answers are "water and mineral ions" and "amino acids and sucrose" respectively.

For the xylem, it usually transports water and mineral ions that are absorbed from the root hair cells up to the leaves, where photosynthesis take place. Water is one of the necessary substance for photosynthesis to take place, while different mineral ions can help the plant by for example Magnesium ions can help produce chloroplast.

While phloem transports amino acid and sucrose from the location of production (eg. Leaves by photosynthesis) to the place where it is used or stored. Plant needs these substances to generate energy for activities such as growth by for example cellular respiration. This process is called translocation.

Both of these tubes help transport substances in the plant, in order to keep the plant alive.