The correct answer is (a) transport of water.
Explanation:
Xylem is a type of vascular tissue in plants that is specifically designed to transport water and dissolved minerals from the roots to the leaves. Water is absorbed by the roots and then travels up the xylem vessels to the rest of the plant. This process is essential for the plant’s survival as water is needed for photosynthesis and other vital functions.
Why other options are incorrect:
(b) transport of food:
Food (sugars and other organic compounds) is transported by the phloem, another type of vascular tissue.
(c) transport of amino acids:
While some amino acids may be transported in the xylem, their primary transport occurs in the phloem. Xylem plays a minor role in amino acid transport, mainly for translocation from roots to leaves.
(d) transport of oxygen:
Oxygen is not transported by the xylem. Plants obtain oxygen through gas exchange from the atmosphere via stomata in their leaves.

The correct answer is (a) transport of water.
Explanation: Xylem is a vascular tissue in plants that primarily functions to transport water and dissolved minerals from the roots to the rest of the plant.
Why other options are incorrect:
(b) transport of food: Food is transported by phloem, another type of vascular tissue.
(c) transport of amino acids: Amino acids are transported through both xylem and phloem, but primarily phloem.
(d) transport of oxygen: Oxygen is transported through diffusion in plants, not xylem.