The earth's surface features are constantly changing in a process known as weathering and erosion. Weathering would happen when rocks would break physically like frost shattering while erosion happens when sediments and rocks are moved from one place to another by agents like water, gravity, wind and ice. These two occurrences are the cause of the constant change of the Earth's surface.<span />
El huevo amniótico de reptiles y aves está rodeado por una cáscara externa resistente que protege al huevo de los depredadores, patógenos, daños y secado.
