Section 1
Human Bodies Progress Through Four Life Stages
People develop through infancy, childhood, adolescence, and adulthood. Each stage brings distinct physical, mental, and social changes as bodies grow and mature at different rates.
In this Grade 7 Life Science lesson from Chapter 21, students explore the four stages of human development — infancy, childhood, adolescence, and adulthood — examining the physical, mental, and social changes that occur at each stage. Students learn how body systems such as the digestive and nervous systems grow and mature throughout development, and how these systems continuously interact to maintain overall health. The lesson also introduces the Apgar score as a tool for evaluating newborn health, connecting biological concepts to real-world medical practice.
Section 1
Human Bodies Progress Through Four Life Stages
People develop through infancy, childhood, adolescence, and adulthood. Each stage brings distinct physical, mental, and social changes as bodies grow and mature at different rates.
Section 2
Body Systems Work Together to Maintain Health
Every system constantly interacts with others to keep the body functioning. The respiratory system supplies oxygen to blood cells while the circulatory system transports hormones throughout the body.
Section 3
Adolescents Experience Dramatic Physical Changes
During puberty, hormones trigger reproductive system maturation, secondary sexual characteristics develop, and growth accelerates. Adolescents typically grow about 10 centimeters taller each year during this stage.
Section 4
Life Expectancy Increases Over Time
Average lifespan in the United States rose from 47.3 years in 1900 to 76.9 years in 2000. This dramatic improvement reflects advances in healthcare, nutrition, and overall living conditions.
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Section 1
Human Bodies Progress Through Four Life Stages
People develop through infancy, childhood, adolescence, and adulthood. Each stage brings distinct physical, mental, and social changes as bodies grow and mature at different rates.
Section 2
Body Systems Work Together to Maintain Health
Every system constantly interacts with others to keep the body functioning. The respiratory system supplies oxygen to blood cells while the circulatory system transports hormones throughout the body.
Section 3
Adolescents Experience Dramatic Physical Changes
During puberty, hormones trigger reproductive system maturation, secondary sexual characteristics develop, and growth accelerates. Adolescents typically grow about 10 centimeters taller each year during this stage.
Section 4
Life Expectancy Increases Over Time
Average lifespan in the United States rose from 47.3 years in 1900 to 76.9 years in 2000. This dramatic improvement reflects advances in healthcare, nutrition, and overall living conditions.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter