The structures forming the brain stem include
1. the pons
2. the medulla oblongata
3. the midbrain
a 1 and 2 only
b 1 and 3 only
c 2 and 3 only
d 1, 2, and 3

D 1, 2, and 3

Explanation:

Midbrain, pons and medulla oblongata together make the brain stem. The midbrain has the reflex center for the tactile, visual and auditory response while pons serves in the regulation of breathing rate.

Midbrain also contains tracts that pass between cerebrum and cerebellum or spinal cord and serves as a relay station for the same. Medulla oblongata has reflex centers for the heartbeat, breathing, vasoconstriction, sneezing, swallowing, etc.

hey there!

so, when you eat, your teeth chew and grind food into smaller pieces. this is mechanical digestion. then reactions aided by digestive enzymes break down large food molecules into smaller molecules. this is chemical digestion. the two processes change the food into simpler substances that can be used by the body for raw materials and energy.

hope this

tobey