(i) For brushing teeth, we only need a small amount of water. A mug full of water is enough, whereas a bucket would be wasteful. (ii) For bathing, a bucket of water is typically sufficient. A tank would hold much more water than needed for one person's bath. (iii) To prepare 2 glasses of lemon water, we need approximately 2 glasses of water, which a jug can easily provide. A bucket would be excessive. (iv) For watering a single plant, a mug of water is usually enough. A bucket would provide more water than needed for one plant.