Evolution. Like how we evolved from apes.
Drinking water shortages? Water across the world isn't purified which without purification doesn't quench thirst.
The atmosphere is the part of the carbon and water cycles but absent from the phosphorous cycle. Carbon cycle depends on photosynthesis and respiration. Water cycle connects aquatic and terrestrial biomes.
Schwann - In 1839, he cells are the basic unit of animal structure
Schlieden - In 1838, he discovered cells are the basic unit of plant structure
Hope this helps
