Malik and his family came to the us a few years ago. they've managed to carve out a nice, middle-class lifestyle that they could never have imagined in their home country. through letters and phone calls, they convince their friends and extended family to come and settle in the same area. this is a pattern known as migration.

Chain migration

Explanation:

In sociology, the term chain migration refers to the process by which migrants from a particular town follow others from that town to a particular destination.

In this example, Malik and his family came to the US a few years ago, now, they convinced their friends and extended family to come and settle in the same area. We can see that his friends and family would go to the same destination were Malik is and they were convinced by him, therefore, this would be a pattern of chain migration.

  b.

there are isolated pockets of farming, generally around rivers and oases, which are used for irrigation.