Stems are
Positively phototropic
Negatively geotropic
Negatively hydrotropic
All of the above
Potato is $(underground)$ stem because it
A runner of water with one thick internode, found in aquatic rosette plants like Eichhorina $(Water\,\, hyacinth)$ is called
Which is not a modification of stem?
In Passiflora, the tendrils are modified