The hemoglobin test is often used to check for anemia, usually along with a hematocrit or as part of a complete blood count (CBC) . The test may be used to screen for, diagnose, or monitor a number of conditions and diseases that affect red blood cells (RBCs) and/or the amount of hemoglobin in blood.he hemoglobin test is often used to check for anemia, usually along with a hematocrit or as part of a complete blood count (CBC) . The test may be used to screen for, diagnose, or monitor a number of conditions and diseases that affect red blood cells (RBCs) and/or the amount of hemoglobin in blood.
Volcanoes form at hot spots in the Earth's crust, at convergent plate boundaries where subduction of oceanic crust is occurring, and at divergent plate boundaries where gaps i â¦ n the crust are being infilled with rising magma.
What causes volcanic eruptions? Quick Answer. Volcanic eruptions occur when magma builds up beneath the Earth's crust and forces its way to the surface. Natural vents in the crust allow magma passage to the surface, and eruptions occur when the magma that forms is less dense than the material above it, causing it to flow upward.