If u read all the time it will build up your concentration and it will also help u remember stuff that is in your memory
Answer:
Vacuum
Explanation:
The other two options are plural, there is no way that can go in the blanks.
Spring (hydrology)
A spring may be the result of karst topography where surface water has infiltrated the Earth's surface (recharge area), becoming part of the area groundwater. The groundwater then travels through a network of cracks and fissure—openings ranging from intergranular spaces to large caves. The water eventually emerges from below the surface, in the form of a karst springs.
A cell; biology. is this what you mean?
whih kind of pedestrian please be specific