Lesson 4: Humans Breathe

         ( A )    HUMANS NEED AIR TO BREATHE

The air that flows into the lungs contains more oxygen and the air that flows out contains more carbon dioxide.



( B )  HUMANS EXCRETE AND DEFECATE

Human excrete urine and sweat to get rid of waste materials from their bodies.

When we defecate, our bodies get rid of undigested food or waste materials called faeces.

( C )  RESPONSE TO STIMULI

Move the hand away from the hot objects

( D )  HUMANS REPRODUCE

Humans reproduce by giving birth to their offspring.