Which of the following endocrine glands is unpaired?

Label the endocrine glands in the figure.

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 the spinal cord to muscles.
$(iii)$ Motor neurons carry signals from receptors to the spinal cord.
$(iv)$ The path through which signals are transmitted from a receptor to a muscle or a gland is called a reflex arc.

$(a)$ Draw a diagram of the human brain.
$(b)$ Label the Cerebrum and Cerebellum on it.
$(c)$ What is the role of the Cerebellum?

Which of the following plant hormones acts as a growth promoter?

The growth of tendril in pea plants is due to: