How are arthropods able to move despite having a hard exoskeleton

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).

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added