The level of the water in the open aquarium tank goes down each day. why?

The water is evaporating slowly ...speciallyif u havea heater in ur aquarium..

Well it since it's a open aquarium it's most likely evaporating

Iam on that question know can you tell me the answer i am realy strruglingasap

Iassume the answer is 75 feet. inwards to outwards rather than outwards to inwards. probably be 75.hachures are stokes drawn in direction of the steepest slope. a series of short parallel lines drawn on a map to indicate topographic relief. it is actually called hachures on contour lines. the small marks in the center of the feature are called hachures.observe the picture attached