What is probably the single most important influence on growth at ...

[karlynnae]

What is probably the single most important influence on growth at all stages of development?
 
  a. Nutrition c. Culture
  b. Heredity d. Environment

Question 2

The karyotype of a person is 47, XY, +21. This person is a:
 
  a. Normal male. c. Normal female.
  b. Male with Down syndrome. d. Female with Turner syndrome.

[Fayaz00962]

Answer to Question 1

ANS: A
Nutrition is the single most important influence on growth. Dietary factors regulate growth at all stages of development, and their effects are exerted in numerous and complex ways. Adequate nutrition is closely related to good health throughout life. Heredity, culture, and environment all contribute to the child's growth and development; however, good nutrition is essential throughout the life span for optimal health.

Answer to Question 2

ANS: B
This person is male because his sex chromosomes are XY. He has one extra copy of chromosome 21 (for a total of 47 instead of 46), resulting in Down syndrome. A normal male would have 46 chromosomes. A normal female would have 46 chromosomes and XX for the sex chromosomes. A female with Turner syndrome would have 45 chromosomes; the sex chromosomes would have just one X.