a solar eclipse, when the moons shadow comes between the sun and earth
Abrasion is caused by the effects of wind and sand.
Bands of soft rocks like clay and sand are very weak in which they can be eroded very quickly. Since cliff and coastline doesn't erode at the the same pace, an inlet of the sea to where the land curves inward forming a bay. Once soft rocks are eroded inward, the hard rocks are able to stick to the sea to form a headland
They can be replaced naturally.
The three means by which the early Polynesian sailors were able to navigate vast regions of the Pacific were by watching the motion of specific stars, weather and seasons of travel and direction, size and speed of ocean waves. The correct options among all the options that are given in the question are option "a", "b", "c".