Sue sees her mother knitting a sweater. later, sue takes out a ball of yarn and some knitting needles from her mother's supplies and tries to do the same. this is a good example of the of gender development.

The missing text is "social learning theory". This theory indicates that the development of the genre has much to do with the imitation of the role models, in this case Sue's mother, she is the closest example of femininity that her daughter has. Sue will continue imitating her mother in all she can.

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.