How and why does your body form a scab after you get a cut or scrape

When you get a cut or scrape Platelets stick together like glue at the cut, forming a clot. As the clot starts to get hard and dries out, a scab forms. That makes sure that you do not bleed consistently.

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.

geologic time scale (for gradpoint) =)