D. high and low levels of silica in the different type of lava.
Explanation:
The volcanoes have different types of explosions. Some tend to be highly explosive, some less explosive, some don't have explosions at all, while some have combinations of different eruptions. The reason for this diversity in the eruption types is mostly the composition of the magma, or rather how high is the silica content in it.
Basically, the higher the silica level in the magma the higher the explosiveness, and the lower the silica level the lower the chances of explosiveness. This is the case because the higher amount of silica makes the magma thicker, so the gasses are trapped and they explode, while when the lower silica content makes the magma less thick, so the gasses are not trapped and explosions are lacking.
Answer:
B. market
Explanation:
A market economy is an economic system in which the decisions regarding investment, production and distribution are guided by the price signals created by the forces of supply and demand. The major characteristic of a market economy is the existence of factor markets that play a dominant role in the allocation of capital and the factors of production.
Carbonate rocks, like limestone <span><span>dolomite's, and chalk on earth</span> </span>
Answer:
Two important measures of a population are population size, the number of individuals, and population density, the number of individuals per unit area or volume. Ecologists estimate the size and density of populations using quadrats and the mark-recapture method.
Explanation:
Economic opportunities seems to be the driving factor for migration nowadays. An example of a group of migrants migrating from areas with a lack of economic opportunities to areas with more economic opportunities are Mexican immigrants seeking job opportunities.
