By What Age Are Most Normal Children Able to Speak

question 53

Multiple Choice

By what age are most normal children able to speak in two- to three-word sentences,using generally correct syntax,although they may make some common errors?

• A) 10 months of age
• B) 7 months to 1 year of age
• C) 1 to 2 years of age
• D) 2 to 3 years of age

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Definitions:

Primitive Streak

Dynamic, constantly changing structure that forms at the midline of the blastodisc in birds, mammals, and some other vertebrates. It is active in gastrulation as cells migrate to a narrow furrow at its center, the primitive groove, and sink into the interior of the embryo. The anterior end of the primitive streak is Hensen’s node.

Epiblast

An early embryo layer from which all the three primary germ layers develop during gastrulation in the formation of a vertebrate body.

Notochord

A flexible rod-like structure in the early stages of embryos in all chordates, providing skeletal support.

Blastocoel

The fluid-filled cavity of a blastula.