51) Research on children’s development of motor milestones suggests that a. this process is primarily a biological one and reflects innately programmed changes consistent across cultures. b. motor developments are dependent on physical maturation, which is guided by our biological changes. c. motor development is purely an environmental process, and is not limited by physiological constraints. d. while there are physiological limits on development, parenting styles and culture shape the variations in motor development. 52) Which of the following infants is most likely to have the fastest motor development? a. An infant born in Peru b. An infant born in the West Indies c. An infant born in Northern Canada to an Inuit family d. An infant born in China 53) Over the course of development, the absolute size of the head continues to ______________, but grows at a _____________ rate than the torso or legs. a. decrease; slower b. increase; slower c. decrease; faster d. decrease; faster 54) The size of the head, in proportion to the rest of the body, is about _____ percent of the total height when an individual is 5 months old. a. 15 b. 20 c. 25 d. 30 55) The size of the head, in proportion to the rest of the body, is about _____ percent of the total height when an individual is 26 years old. a. 15 b. 20 c. 25 d. 30 56) The body’s reproductive organs are called a. thyroid glands. b. primary sex characteristics. c. secondary sex characteristics. d. adrenal glands. 57) Breast development is to ______________ sex characteristics as penis enlargement is to ______________ sex characteristics. a. primary; primary b. primary; secondary c. secondary; primary d. secondary; secondary 58) What is the best explanation for why the age of menarche has decreased over the past century from around 15 to around 13 years of age? a. Advances in technology correspond to an earlier age of being able to carry an infant to term. b. Evolutionary changes are linked to taller and more physically strong women that develop earlier. c. The change is probably due primarily to better nutrition and health care. d. The decrease reflects the revolving cycle where women are having children younger and, in turn, the age of reproduction of their children is younger, and so on. 59) Physical maturity is most closely related to the onset of which of the following? a. Spermarche b. Menarche c. Androgens d. Secondary sex characteristics 60) During menarche adolescents experience a. the end of menstruation. b. the first ejaculation. c. the start of menstruation. d. voice changes.