Changes that tell them apart
Sort six changes of adolescence and find the four that help tell males from females.
A moustache, and a taller friend
Venkatesh has a thin moustache. Devyani has grown taller. Both are changes of adolescence.
Which of the two changes helps you tell a boy from a girl?
What this lesson covers
The idea
Changes such as voice change, growth of facial and chest hair in boys and development of breasts in girls are not directly involved in reproduction but help distinguish males from females; they are called secondary sexual characteristics.
A moustache, and a taller friend
Venkatesh has a thin moustache. Devyani has grown taller. Both are changes of adolescence.
Which of the two changes helps you tell a boy from a girl?
- Growing taller
- The thin moustache
- Both of them, equally
Who has the change?
Tap a change, then tap the row where it is seen: in boys, in girls or in both.
Secondary sexual characteristics
Changes such as a change in voice, facial and chest hair in boys and development of breasts in girls are not directly involved in reproduction, but they help distinguish males from females. They are called secondary sexual characteristics.
Growing taller and gaining weight happen in both boys and girls.
- Change | Seen in
- Change in voice | boys
- Facial hair | boys
- Chest hair | boys
- Development of breasts | girls
Notes
A change in voice, facial and chest hair in boys and development of breasts in girls are not directly involved in reproduction, but they help distinguish males from females. They are called secondary sexual characteristics.
Check yourself
These changes help tell males from females, but are not directly involved in reproduction. What are they called?
In the sorted picture, how many changes carry a star? The star marks a secondary sexual characteristic.
Answer: 4
Four: a hoarse voice, moustache and beard, chest hair, and development of breasts.
In adolescent boys the voice box grows and the voice sounds hoarse. What kind of change is this?
What is true about secondary sexual characteristics?
- Parts that take part in reproduction. These changes are not directly involved in reproduction.
- Secondary sexual characteristics — correct. Yes! That is the name for such changes.
- Chemicals that are made in the body. Those are hormones. These changes have a different name.
- A secondary sexual characteristic — correct. Yes! It is not directly involved in reproduction, but it helps tell males from females.
- A change directly involved in reproduction. It is not directly involved in reproduction.
- A change that happens only in girls. The hoarse voice is described for boys. Girls' voices change only slightly.
- Every boy gets them at exactly the same age. The timing varies from person to person, and that is completely normal.
- They are directly involved in reproduction. They are not directly involved in reproduction.
- They help distinguish males from females — correct. Yes! That is why they have this name.