Answer:
1. Volcanic activity can shape a coast in several ways. One way is through the creation of new land masses, such as islands or peninsulas, which can alter the shape of the coast. Volcanic activity can also produce coastal features such as cliffs, sea stacks, and beaches. Lava flows can create new land and alter the coastline, while volcanic ash and debris can build up and create new land masses or alter the shape of existing ones.
2. Coastal erosion tends to produce a straight shoreline over time because the forces of waves, currents, and tides tend to wear away the coastline evenly. This can result in a coastline that appears straight, as opposed to one with many inlets and bays. Additionally, as sediment is eroded from one area of the coast, it may be deposited in another area, creating new land masses and altering the shape of the coastline. Over time, these processes can lead to a more uniform and straight coastline.