Biology: Age 12
15 illustrated Biology lessons for Age 12.
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Rods and Cones in the Eye The retina lines the back of the eye. Rod cells help you see shapes in dim light, while cone cells help you se… -
Genes and Traits Genes are sections of DNA. They carry instructions that help build and run a body, and they can affect visible… -
Eyes, Ears, and the Fear Switch Light and sound enter through your eyes and ears. Signals travel through a brain relay to two almond-shaped cl… -
Cat Purr Vibrations A cat's purr starts when air moves from the lungs through the trachea. The moving air makes thin folds in the … -
Virus Entering a Cell A virus attaches to the outside of a cell and sends its genetic material inside. The cell then makes new virus… -
Underground Root Threads Below the soil, pale threads join the roots of different plants. Water, nutrients and warning signals can trav… -
Sunlit Slope and Rising Air Sunlight warms the rocky slope, and the air just above it becomes lighter. That rising air forms a column that… -
Warm Sand Nest A buried clutch of eggs rests in a flask-shaped chamber under the sand. The sand near the middle is warmer tha… -
Warm Sand and Sea Turtle Eggs Sea turtle eggs do not get their sex only from genes. The temperature of the sand around each egg decides whet… -
Air's Path Through the Body When you breathe in, air enters through your nose or mouth and travels down a tube in your neck. It then split… -
Giraffe Bending to Drink A giraffe lowers its long neck to a pool. Special neck arteries and one-way valves keep blood moving to its he… -
Warm Sand, Cool Sand A crocodile egg's sex is decided while it incubates, not by chromosomes like in mammals. Eggs in a warm nest o… -
Muscle pairs at the elbow When you bend your arm, the muscle at the front of your upper arm gets shorter and fatter. The muscle behind i… -
Animals Carry Seeds Rainforest trees often make fruit that animals eat. The animals carry the seeds away in their dung or on their… -
Same Bones, Different Jobs Humans, whales, bats, and horses have forelimbs built from the same set of bones. Those bones are shaped and s…