Clues to Adult Height: teacher key

How You Grow, grade 10 edition, written for 10th grade. The most accurate way doctors guess adult height uses a child's current height with a bone age X-ray. Rules of thumb and the mid-parental method can miss.

Read the book. Print this page for the key.

Questions and answers

1. Which method do doctors use as the most accurate way to guess adult height?
   • Doubling a child's height at age 2
   • A child's current height with a bone age X-ray (answer)
   • Counting how many genes a child has
2. About how far off can the mid-parental method be?
   • About 4 inches up or down (answer)
   • About half an inch
   • About 2 feet
3. What does polygenic mean in the phrase polygenic trait?
   • Controlled by one gene
   • Controlled only by the growth plates
   • Controlled by many genes, each with a modest effect (answer)
4. What does a closed growth plate tell you about a bone?
   • It is still getting longer
   • It is no longer growing longer (answer)
   • It has stopped being living tissue
5. Why is the doubling rule not a good way to guess adult height?
   • It only works for girls
   • It uses the wrong bone
   • No research shows that it is accurate (answer)

Words

• polygenic: from many genes
• cartilage: rubbery tissue
• atlas: picture book
• variants: gene versions