The growth of pollen tubes towards ovules is due to

'Brain and spinal cord are two vital organs of our body'. How is our body designed to protect them?

In a neuron,conversion of electrical signal to a chemical signal occurs at/in

Which of the following statements are true?
$(i)$ Sudden action in response to something in the environment is called reflex action.
$(ii)$ Sensory neurons carry signals from spinal cord to muscles.
$(iii)$ Motor neurons carry signals from receptors to spinal cord.
$(iv)$ The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc.

Name the hormone synthesized at the shoot tips. How does it help the plant to respond to light?

What is the gap between two neurons called?