46.Which of the following diseases is more common amongst agricultural workers as compared to urban population ?

47.Which of the following plants is effective in reducing water pollution and is also useful for producing biogas ?

48.The age of a tree can be determined more or less accurately by

49.The seed of the cotton plant bears relatively long hairs and much shorter hairs which remain attached to the seed. The shoter hairs are referred to as

50.Which of the following should be done if there is a reduced uptake of water by the roots of a plant ? 1. Transfer from outdoors to indoors 2. Removal of half of its leaves 3. Spraying with abscisic acid