(N/A) $(1)$ When plant cells and animal cells are placed in a hypertonic solution,exoosmosis occurs. In plant cells,the cytoplasm shrinks and separates from the cell wall,a process known as plasmolysis. However,animal cells lack a cell wall; therefore,the entire cell shrinks as water leaves the cytoplasm,eventually leading to cell death. Thus,plasmolysis is a characteristic feature of plant cells due to the presence of a rigid cell wall.
$(2)$ Wood is a colloidal system that absorbs water from its surroundings in large amounts,a process called imbibition. During the monsoon,the humidity in the air increases,causing the wood in doors and windows to absorb moisture,which leads to swelling.