Read the following passage and answer the item that follows. Your answer to this item should be based on the passage only.

More than three-quarters of the world's flowering plant species rely on animal pollinators, chiefly insects, and pollination underlies a substantial share of global food and medicinal-plant production. Bees alone are essential to several hundred crop species. Because pollination depends on an intricate web of relationships between plants and their pollinators, losing either side of that relationship threatens the other, and maintaining pollinator populations requires resources such as patches of undisturbed natural habitat near cultivated land.

On the basis of the passage given above, the following assumptions have been made:

1. Sustainable food production for staple grains is impossible without pollinator diversity.

2. Growing a single crop over large areas can undermine pollinator survival.

3. Pollinators are scarce in farmland that lacks nearby natural habitat.

Which of the above assumptions is/are valid?