Thigmotropism is the response of the plant to

Plant movement in response to diffuse stimulus of light is

Coiling of garden pea tendrils around any support is an example of

During experimentation, why is it difficult to attribute any observed effect to a single hormone?

Name a hormone which:
$(A)$ is gaseous in nature
$(B)$ is responsible for phototropism
$(C)$ induces femaleness in flowers of cucumber
$(D)$ is used for killing weeds (dicots)
$(E)$ induces flowering in long day plants

Which of the following sets is not a natural plant growth regulator?