Answer:
Spiral Galaxy
Explanation:
There are four main categories of galaxies: elliptical, spiral, barred spiral, and irregular. These types of galaxies are further divided into subcategories while at the same time other types of galaxies exist based on their size and other unique features. The most common type of galaxy found throughout the universe is the spiral galaxy.
The reactivity of a metal is determined by how tightly the metal holds onto the electrons in the outermost energy levels (valence electrons)
The major carbon sources (reservoirs that release more carbon than absorbed) are: deforestation and fossil fuels
The major carbon sinks (reservoirs that absorb more carbon than released) are:
soil, oceans and plants.
When scientists calculate the amount of carbon dioxide is returned to the atmosphere vs the released the amount of carbon, a large amount is unaccounted for and the total does not add up. This is why scientists believe there is an undiscovered carbon sink somewhere.