Examination of the Ages at Which Children Achieve Motor Milestones

question 131

Multiple Choice

Examination of the ages at which children achieve motor milestones shows that:

• A) practice has little effect on the ages at which babies master universal skills.
• B) 90 percent of infants have begun walking by the time they are 12 months of age.
• C) there are wide variations in the ages at which infants begin to sit, walk, and crawl.
• D) infants are remarkably uniform in the ages at which they become able to sit, crawl, and walk.

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Definitions:

System Optimization

The process of making a system as effective or functional as possible by adjusting its components and operations.

Lithosphere

The rigid outer layer of the Earth, consisting of the crust and upper mantle.

Upper Mantle

The portion of the Earth's mantle that lies just beneath the crust, extending to a depth of about 660 kilometers.

Nitrogen Cycle

The series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms, including nitrogen fixation and decomposition.