a volcano is a mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust.
There are three main types of volcano - composite or strato,shield and dome. Composite volcanoes, sometimes known as strato volcanoes, are steep sided cones formed from layers of ash and [lava] flows. The eruptions from these volcanoes may be a pyroclastic flow rather than a flow of lava.
The answer is <span> an endothermic reaction. </span>Photosynthesis is a type of endothermic reaction because it needs the energy from light (sun) to convert water and carbon dioxide into oxygen and glucose needed by other organisms.
Because human DNA is so very long (with up to 80 million base pairs in a chromosome) it unzips at multiple places along its length so that the replication process is going on simultaneously and more accurately.
