What are three aesthetic ways our skin can change as we age? Which one(s) could be indicative of a medical issue?

Aging skin looks thinner, paler, and clear (translucent). Large pigmented spots, including age spots, liver spots, or lentigos, may appear in sun-exposed areas.

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Sunlight can cause:

Loss of elasticity (elastosis)

Noncancerous skin growths (keratoacanthomas)

Pigment changes such as liver spots.

Thickening of the skin.

Explanation:

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.