Astronomers Have Realized That the Surface of Ida Is Older

question 4

Multiple Choice

Astronomers have realized that the surface of Ida is older than the surface of Gaspra. How do they measure this?

• A) we have radioactive rock samples from each asteroid to analyze
• B) the surface composition (elements and compounds) can easily tell us the ages
• C) from counting craters on each asteroid's surface
• D) from the magnetic field of each body, which weakens with age
• E) it's purely a guess; astronomers have no way of really measuring the ages of these asteroids

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Definitions:

Bone-Forming Cells

Cells known as osteoblasts that are responsible for the synthesis and mineralization of bone during both initial bone formation and later bone remodeling.

Ossification

The process of bone growth.

Endochondral

A type of ossification in which bones start out as cartilage models.

Occipital Bone

a bone situated at the lower back part of the skull, supporting the back of the head and containing the foramen magnum.