The correct answer is C. both (a) and (b).
The Paleozoic era was a time of great geological activity. The Caledonian mountain range rose in the northern hemisphere, while the Appalachians and Central European mountains rose in the southern hemisphere. Life also came ashore during this time, and the first animals to do so were invertebrates.
The Caledonian mountain range was formed when the continents of Laurentia and Baltica collided. This collision caused the Earth’s crust to fold and buckle, creating a mountain range that stretched from Greenland to Scotland. The Appalachians and Central European mountains were formed when the continents of Gondwana and Laurasia collided. This collision also caused the Earth’s crust to fold and buckle, creating a mountain range that stretched from North America to Europe.
The first animals to come ashore were invertebrates, such as sea scorpions and trilobites. These animals were able to survive on land because they had hard exoskeletons that protected them from the elements. They also had gills that allowed them to breathe underwater.
The Paleozoic era was a time of great change and upheaval. The Earth’s surface was constantly changing, and life was also evolving rapidly. The first animals to come ashore were a major milestone in the history of life on Earth.