### exchange:

Voluntary exchange
* gives people a broader range of choices in buying goods and services.
* is the only way one can obtain wealth in a free market.
* occurs when all parties to the exchange expect to benefit.
* plays a greater role in the allocation of goods and services.
* win-win situation since both parties expect to gain.

### excision:

Surgical removal
* are excision
  - surgery
* depends on whether the cancer has spread to local tissues.
* is curative for many orbital tumors including optic nerve glioma and meningioma
  - just one of a number of ways in which they can be treated
* is the fibrosis
  - only treatment for disfiguring or potentially cancerous papillomas
* is the therapy of choice for basal cell carcinoma
  - squamous cell carcinoma
  - treatment of choice for most functioning adrenal tumors
* remains the only form of therapy proven to prolong survival.

Excited state
* Most excited states decay very rapidly, others a little less so.
* are of higher energy
  - stronger acids and stronger reductants than the original ground states

Excited trembling
* A trembling is motion
* Trembling is also manifestations of a weak heart
  - an excited state

### excreted renally:

Excess phosphorus
* can increase algal growth, which can cause a greenish tint to the water
  - interfere with the availability of copper and zinc
* is excreted renally.
* precipitates with iron, reducing available iron.
* runs off into lakes and streams and promotes algae growth, reducing water quality.
* stimulates the parathyroid gland to extract calcium from the bones.

Exfoliation
* accounts partly for the rounding of many summits in the highlands.
* can help remove the dull skin, but only if the skin has been sufficiently loosened.
* coaxes the skin to rejuvenate itself as nature intended.
* is also important to keep dead cells buildup to a minimum
  - like exercise for the skin
  - one of the keys to healthy skin, as it helps in keeping pores clean and unclogged
* is the dominant process of physical weathering on the mountain
  - removal of dull, dead surface skin
* normal process for skin cells.
* occurs as sheets or slabs of the cracked rock slip off and become further eroded
  - when deeply-buried rock is exposed at the earth's surface by erosion
* removes all debris and dead skin cells
  - the outer, dead layer of the skin
* softens and smoothes, keeping pores clear and ingrown hairs at bay.
* specific type of mechanical weathering that occurs in granite.
* type of physical weathering that occurs from rock pressure at depth.

### exfoliation:

Dander
* are anger
  - scales
* builds up during the dry winter months.
* causes most cat allergies and is produced regularly.
* common culprit in allergies to dogs.
* is exfoliation
  - inside the hair follicle until it sheds, at which point the dander is in the air
  - minute scales that fall from the hair, feather, and skin of all warm-blooded animals
  - the microscopic particles of skin, fur and hair that animals continually shed
  - usually the simplistic explanation of the cause of animal allergies
* tends to be more of a problem with dogs than cats, although it is common to both.

### exfoliation | dander:

Animal dander
* carries antigens that can cause allergic reactions in sensitive people.
* comes from having pets in the house.
* common allergen.
* consists of tiny flakes of skin shed by animals.
* is one of the leading causes of asthma.
* leading cause of allergy.

### exhilarating science:

Modern astronomy
* branch of graduate level physics.
* is an exhilarating science
  - essentially physics applied to the study of celestial objects
  - made up of several branches
* leans heavily on the concepts and techniques of physics and mathematics.
* uses all regions of the electromagnetic spectrum.