Answer to Question 1
During late middle-childhood, girls and boys start to vary in their growth spurts. At about the age of 10, girls start to spurt in height sooner than boys. Boys start to spurt about two years later, at the age of 12 . Girls and boys reach their periods of peak growth in height about 2 years after the spurt begins, at about age 12 for girls and age 14 for boys. The spurt in height continues for another 2 years, gradually declining in pace. Boys grow more than girls do during their spurt, averaging nearly 4 inches per year during the fastest year, while girls only average 3 inches per year. Overall, boys add an average of 14 and one-half inches to their height during the spurt and girls add a little more than 13 . In terms of weight, the weight spurt begins about a half a year after the spurt in height. As with height, the girls start earlier, and both boys and girls continue to experience a spurt for about two years. Girls are heavier and taller than boys from about age 9 or 10 to about 13 or 14 . Once boys begin to spurt, they catch up with girls and become taller and heavier.
Answer to Question 2
F
Animal extinctions and human population growth.
The Number of Children Americans Think Are Ideal
Growth in Cold and Cool Clouds
Role of Ras protein in a central growth factor activation pathway
Ice cores also preserve a record of ice sheet growth and decay
Growth of World Trade, 1870–2010