Answer:
D. intense volcanic activity.
Explanation:
- The Paleozoic era an era in the geologic time and started about 541 million years. It originated due to the diversity of life forms on the planet. and ended about 252 mn years ago along with the end of Permian era.
- The extinction was related to the changes in climate and exceptionally low sea levels. During which about 95% of the marine species were killed.
<span>Small jagged pieces of rocks, minerals, and volcanic glass the size of sand and silt (less than 2 millimeters (1/12 inch) in diameter) erupted by a volcano are called volcanic ash. Very small ash particles can be less than 0.001 millimeters (1/25,000th of an inch) across.</span>
Many people decided to move from more rural areas that offered land and space for farming to cities that had factories and offered job opportunities
Answer:
Partial melting occurs when only a portion of solid is melted. It is thus enriched in the chemical components of minerals with lower melting temperatures and the remaining unmelted portion of the rock is composed of minerals with highest melting temperatures. Partial melting preferentially enriches melts with incompatible elements.
Partially melted rock do not usually experience complete melting inside the Earth, due to their different chemical composition and their melting points.
It is thought that partial-melting processes play a major role in generating more-defined liquids from less-evolved ones, so that many basalts may be the result of partial melting in the upper mantle, and many granites may have derived partly or completely from the partial melting of continental crust (anatexis).With increasing temperature and pressure, the subducted oceanic crust (of basic composition) first undergoes metamorphism and then begins to melt or release watery fluids; this material rises into the overlying mantle, which may also begin to melt, giving rise to intermediate magma.
Answer:
Option (D)
Explanation:
Organic detritus usually refers to those materials that are the remains of dead organisms such as plants and animals.
The flowing water ecosystem such as the head-water streams obtains most of the materials from the nearby terrestrial and aquatic places due to the surface runoff. It is highly rich in the amount of organic detritus, as the materials such as leaves, branches, roots, soil particles, and other organic waste products are transported from the land areas, thereby obtains its energy from them.
Thus, the correct answer is option (D).
