While using a dichotomouy key to identify a specificities of fish you must start with

the feature the is not shared by all fisj

cell regulation is conducted by special proteins.

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).