Well, it tells you that thoughts (which express theme) and emotions (which express mood) are closely connected, so d. theme and mood are closely linked.
Answer: The type of sentence: Simple
Indoor Plumbing.
Primarily, it has provided a greater level of sanitation in modern life. The use of running water to wash your hands and bathe reduces the likelihood of spreading germs and bacteria. The ability to cleanly remove waste away from heavily populated areas allows for cleaner air, thus, fewer respiratory related illnesses. Ultimately, it has propelled civilizations towards the better quality of life that we enjoy today.