The process in which a mixture of heavier particles and lighter particles are separated by the wind is:

Question

Accepted Answer

The correct answer to the question is Option 2: Winnowing.

1. **Explanation for Option 2 (Winnowing):**
   Winnowing is a process used to separate lighter particles from heavier particles using the wind or air. In agricultural practices, it is commonly used to separate chaff (the husks of grains) from the grain itself. When the mixture is allowed to fall from a height, the wind blows away the lighter chaff, while the heavier grains fall straight down. This method effectively utilizes the difference in weight and density between the two components, making it an ideal process for such separation tasks.

2. **Explanation for why other options are incorrect:**

- **Option 1 (Threshing):** Threshing is a process used to loosen the edible part of cereal grain from the straw to which it is attached. It does not involve the separation of particles by wind. Instead, it involves mechanical action to break the grain away from the husk or stalk.

- **Option 3 (Sieving):** Sieving is a method used to separate particles based on size using a sieve or mesh. It does not involve the use of wind. Instead, it relies on the physical size difference between particles, allowing smaller particles to pass through the mesh while retaining larger ones.

- **Option 4 (Sedimentation):** Sedimentation is a process used to separate particles based on their density by allowing them to settle in a fluid. It does not involve wind. Instead, it relies on gravity to cause denser particles to settle at the bottom of a container, while lighter particles remain suspended or float.

In conclusion, winnowing is the only process among the options that specifically involves the use of wind to separate lighter particles from heavier ones, which is why Option 2 is the correct answer.