On the basis of the passage given above, the following assumptions have been made :
1. Sustainable production of India's cereal food grains is impossible without the diversity of pollinating animals.
2. Monoculture of horticultural crops hampers the survival of insects.
3. Pollinators become scarce in cultivated areas devoid of natural vegetation.
4. Diversity in insects induces diversity of plants.

Which of the above assumptions is/are valid ?

Correct Option: (b) 2, 3 and 4 only

Let us evaluate the assumptions based on the passage: 1. The passage mentions that at least one-third of agricultural crops depend on pollination, but it does not specifically state that sustainable cereal production in India is impossible without it (too sweeping/extreme), so assumption 1 is invalid. 2. The passage notes that effective pollination requires resources like refuges of natural vegetation, implying monoculture hinders insect survival and pollination, making assumption 2 valid. 3. The text explicitly states that effective pollination requires resources such as refuges of pristine natural vegetation, directly supporting the assumption that pollinators become scarce in cultivated areas devoid of natural vegetation (Assumption 3 is valid). 4. The passage notes intricate relationships between plants and animals and that reduction of either affects both, supporting the reciprocal link where diversity in insects correlates with plant dependencies (Assumption 4 is valid). Thus, assumptions 2, 3, and 4 are valid.