When coming to building something, some materials are more vulnerable to water and can wear away easier. Some can keep the water in, so depending on the material, the water quality can be better sustained.
Answer:
The correct answer would be a) circulatory system.
A stroke is primarily caused due to reduced or interrupted supply of blood to the brain.
The blood supply is usually reduced as a result of blockage or bursting of an artery carrying blood to the brain.
Consequently, the brain cells experience a lack of oxygen and nutrients due to which they begin to die.
Thus, stroke is initially caused by damage to the circulatory system.
