Think about it. Caves are dark, with little to no light. If there's no light, why would you need to see? There are far more important senses than sight in cases like these. Senses such as smell, hearing, and touch.
Hope that helped.
That is TRUE, which makes updating maps extremely easy and convenient, not to mention it's the key element in GPS systems.
Answer:
A semipermeable membrane is a barrier that will only allow some molecules to pass through while blocking the passage of other molecules. A semipermeable barrier essentially acts as a filter. Different types of semipermeable membranes can block out different sized molecules. A semipermeable membrane can be made out of biological or synthetic material.
Explanation:
