It rains, water moves and erodes the land and creates valleys and rivers.
The substance is a compound because it's formed by two different elements.
Answer: the relative differences in arrival times of the S and P seismic waves at several recording stations tell scientists about the different speeds those waves were traveling at, which in turn gives information about the density of the material the layer is made of, and how thick the layer is in several directions.
Explanation:Earth's layers
Cells don't grow very big because they have to be able to diffuse through material easily. Also, when cells are small and plentiful they are easy to replace when damaged.
Answer:
Biology can simply be described as the study of living organisms. Biology is divided into many sub categories depending on the features of life that we want to study. For example, molecular biology is the study of molecules which make up living organisms.
Zoology can be described as a branch of biology under which animals are studied. The field of zoology involved studying the taxonomy of animals, their evolutionary histories, physiology, embryology etc. All these studies are parts of biology hence zoology and biology are related.
Apart from these other unifying principles shared between zoology and biology are genetics, cell biology, population biology,biochemistry etc.
