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.
Answer: Answer here
Explanation:
Economic sanctions are commercial and financial penalties applied by one or more countries against a targeted self-governing state, group, or individual. Economic sanctions are not necessarily imposed because of economic circumstances—they may also be imposed for a variety of political, military, and social issues.
Answer:
Deep ocean currents.
Explanation:
In cold regions, such as the North Atlantic Ocean, ocean water loses heat to the atmosphere and becomes cold and dense. When ocean water freezes, forming sea ice, salt is left behind causing surrounding seawater to become saltier and denser. Dense-cold-salty water sinks to the ocean bottom.