Factors affecting sedimentation include the weight of the floc, ________, detention time, and short-circuiting.

The correct answer takes into account both water temperature and water velocity as significant factors influencing sedimentation.

Water temperature affects the viscosity of the fluid and consequently the motion of the floc. Warmer temperatures can decrease the viscosity, allowing for faster movement and interaction among particles, which could enhance or hinder the ability of floc to settle.

Water velocity is crucial because it influences how quickly water flows through the sedimentation tank. High velocities may prevent the floc from settling properly, as they can cause turbulence that keeps particles suspended in the water. Conversely, low velocities promote better settling and allow floc to aggregate and settle more effectively.

Detention time is also mentioned in the question, as it refers to the duration that water is held in a sedimentation tank, allowing particles to settle out. Short-circuiting refers to the phenomenon where water travels through a treatment unit more quickly than intended, which can result in less effective sedimentation.

Considering these explanations, the inclusion of both water temperature and water velocity in the answer reflects a deeper understanding of the physical processes that affect sedimentation.