
Handy Hands: Felix the touch neuron helps Nina discover how hands work, and three young scientists learn the importance of opposable thumbs.

Two Ears: Nina investigates why people have two ears, and Eve, Finlay and Lana help with a listening experiment.

Two Ears: Nina investigates why people have two ears, and Eve, Finlay and Lana help with a listening experiment.

Blood: Nina investigates why people have blood in their bodies, with the help of Luke, her sight neuron.

Blood: Nina investigates why people have blood in their bodies, with the help of Luke, her sight neuron.

Brain: Nina investigates why humans have brains with the help of her five sense neurons.

Brain: Nina investigates why humans have brains with the help of her five sense neurons.