-Salicylic acid is a naturally occurring chemical produced in willow trees. Salicylic acid is used by humans in some acne products to kill bacteria that
cause skin irritation
Based on this information, what stimulus most likely causes willow trees to
increase the production of salicylic acid?
Freezing conditions that damages leaves
Changing seasons with less direct sunlight
Damage to the bark of the tree trunk
Exposure to pathogens in the vascular tissue

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explanation:

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when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.  

answer/// wohler;