Children of mothers who smoked during pregnancy scored nine points lower on intelligence tests at ages three and four than children of nonsmokers.
1. Suggest some lurking variables that may help explain the association between smoking during pregnancy and children's later test scores. The association by itself is not good evidence that mothers' smoking causes lower scores. (Select all that apply.)a. The diet of the child.
b. The psychological condition of the child.
c. The IQ of the mother.
d. The socioeconomic status of the mother.

All of the options apply.

Step-by-step explanation:

In the example given in the question, it is stated that mothers' smoking during pregnancy can affect childs' IQ and can cause lower scores on test.

All of the given options can be given as evidence for the link between smoking and lower IQ. The diet especially throughout childhood has significant effect on the development of the brain and the prefrontal cortex.

The psychological condition that the child is in, the environment in the house that he/she grows up in affects the IQ and the EQ.

The IQ can be affected by outside factors but it also has a relation with the genes that the child takes from his/her parents.

The socioeconomic status of the mother can affect the environment that the child grows up in, the people he/she interacts with and the opportunities that he/she gets to stimulate the brain in different ways to encourage growth.

I hope this answer helps.

3 is greater then both of those numbers