During the early childhood years, the number of words a child uses increases at a rapid pace. this is sometimes referred to as the ch 9

Vocabulary spurt

Vocabulary spurt is vital part of development which occurs during the child’s second year of life. point in During this time,  a child may display an abrupt growth in their verbal vocabulary. This occurs when a child switches from early language learning of approximately two words per week per week to unexpectedly using up to 20 words

answer:

d. because dr. laguardia selected a widely used measure, his study generalizes to has strong external validity. external validity has limited external validity. other applications of this measure.

the widely used measure that he applied to his experiment was the benton facial recognition test. it employed on to football players and as result, only players who suffered brain concussions did not pas this test. and although it has an external validity, it is limited because it isn't general to apply to other population.

yes he did writing dots to make the answer