A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name. Precipitation reactions can help determine the presence of various ions in solution.
This probably won't help since this was a year ago but here it is:
The diaphragm adjusts the amount of light on a light microscope.
C) small, one-celled organisms and primitive jellyfish
A. Sediment
Both weathering and erosion produce sediment
Weathering, by definition, is the physical integration and chemical decomposition of earth materials at or near the earth’s surface. Erosion, by definition, is the gradual destruction of something by natural forces (e.g. water, wind, ice). Therefore, the characteristic of both weathering and erosion is that it occurs naturally.
B) Holding a cat with while wearing heavy glove.
That would be pretty hard.