The largest particles are removed by a) Screening b) Sedimentationc) Filtration and water softening d) All the above

The process of removing the largest particles from water can be achieved through various methods.

a) Screening: This is the first step in water treatment where water passes through screens to remove large particles like leaves, trash, and other large particles that could block other equipment.

b) Sedimentation: This process involves allowing the water to sit undisturbed while heavier particles sink to the bottom due to gravity. The settled particles, known as sludge, are then removed.

c) Filtration and water softening: Filtration is the process of passing water through a porous material to remove particles suspended in water. Water softening is a process that reduces the concentration of calcium, magnesium, and certain other metal cations in hard water.

d) All the above: All these processes are involved in the removal of particles from water, from the largest to the smallest. Therefore, the answer is d) All the above.