During the period of the _______________, the longest stage of prenatal development, the infant reaches the age of viability. After this point in the pregnancy, the child would be capable of surviving outside of the mother's body

By the age of ten months, an infant will generally

A) use only the phonemes of the native language of adult speakers around them. B) be in the cooing stage of vocalization. C) have a vocabulary of approximately 100 words. D) speak in two-word "sentences."

The term "concrete" is used to describe concrete operations because

a. understating reversibility at this stage is so hard (like concrete). b. once a child focuses on one aspect of a task, his thinking appears to be unmovable (set in stone or concrete). c. the path of understanding is paved with challenges (like a concrete road). d. individuals in this stage can mentally manipulate objects as long as they are present (concrete example).