The correct answers are as follows:
1. In a plant stem, the vascular tissue is CONTINUOUS FROM THE ROOTS TO THE LEAVES.
In plants, vascular tissues refers to a conducting tissue, which is found in most vascular plants. The conducting tissue is made up primarily of xylem and phloem, which transport water and nutrients to all parts of the plant's body. The continuation of the vascular tissues from the root to the leaves allow them to transport the needed materials to all parts of the plants.
2. The function of the leave that is taken up by the stem of such cacti is PHOTOSYNTHESIS.
Cacti is a kind of plant that is found in hot and dry climates, because of this, the plant has to adopt some adaptations, which reduces the amount of water that is lost from its body. One of this adaptations is the absence of leaves, through which water can easily evaporate. Because cacti lack leaves, they utilize their stem instead in the process of photosynthesis.