8. The two main sources of dissolved substances (such as salts) in seawater are volcanic eruptions from the Earth's interior and . * 1 point
a. chemical weathering of continental rocks
b. earthquakes at the continental margins
c. physical weathering of oceanic rocks
d. none of the above

Different researchers break the life cycle of humans into different number of stages. The life cycle of the humans can be categorized into:

Pregnancy: During pregnancy, an embryo is formed from a zygote. Then, eventually a fetus is formed.

Infancy: Infancy can be described as the earliest period after a child is born.

Childhood: The age where the child starts to learn from his environment.

Puberty: The beginning of adolescence is known as puberty. It is the time when various hormonal changes occur.

Adolescence: The late teen ages.

Adulthood: The age when the person has passed the teen ages.

Old age: People above the age of fifty.