Usually, when sludge is removed from __________, it is left in heaps next to the drain for 3–4 days. Examisthan.com | Source: Grade 6 Science — Curiosity (Reprint 2026–27) Page 4
drains
○ water's
○ humidity
○ expresses
Show explanation
The textbook states: “Usually, when sludge is removed from drains, it is left in heaps next to the drain for 3–4 days.” — Examisthan.com