### rare:

Allergic response
* are rare
  - varied and unique to each child
* can range from mild skin irritation to life-threatening anaphylactic shock.
* require allergen-specific IgE to be already present, bound to mast cells.

Anaphylactic reaction
* are rare
  - severe and require immediate medical attention
  - usually quite sudden and severe
  - very unusual
* can follow rupture of an echinococcus cyst
  - manifest themselves in several different ways
  - occur in rare instances
* caused by food allergies can be potentially life-threatening.
* tend to be faster and more severe with each exposure to the allergen.

Decubitus ulcer
* All decubitus ulcers have a course of injury similar to a burn wound.
* is ulcer
* term doctors use to describe any such sore.

Human toxicity
* is rare.
* is, however, hard to avoid with pesticides targeting mammals, such as rodenticides.
* varies greatly from compound to compound.

Lymphatic metastasis
* Lymphatic metastases are likely to appear in the pararectal, internal iliac , or sacral lymph nodes.
* can also be present in the supraclavicular nodes.

Physiological disorder
* Some physiological disorder occurs in winter.
* result from major and trace element imbalances.

Retinal hemorrhage
* are always significant, reflecting vascular disease that usually is systemic
  - extremely uncommon in severe accidental brain injury
* can also occur, and sometimes shaken-baby syndrome is erroneously diagnosed
  - be disastrous

Spicy food
* Most spicy food has odor
  - strong odor
* Some spicy food helps metabolism.
* are rare.
* can induce urticaria
  - irritate the cracks and cause extreme pain
* cause ulcers.
* has effects
* increase the consumption of fluids.
* is too strong for cats.
* prevail in the western mountain regions of Szechuan and Hunan.
* work just like a natural decongestant but without side effects.

Vertebrate fossil
* Most vertebrate fossils are rare.
* Some vertebrate fossils are very large
  - small
* bear valuable information about the past.

Wheat allergy
* Some wheat allergies allow the use of rye bread as a substitute.
* Wheat allergies are usually a reaction to the gluten found in the wheat berry.

### rate:

Birth rate
* are lower in all socioeconomic groups
  - rates
* continue to decline in all regions of the world
  - fall, and far fewer people are coming into the labour market
* depend on both the fertility rate as well as the age distribution of a population.
* differ considerably by educational attainment.
* is linked to poor health and child mortality.
* show a continued decline, even in states with persistent high fertility.

Bit rate
* describes a file's transmission speed.
* is one means used to define the amount of compression used on a video signal.
* refers to the speed at which the processor can read and process data from the disc.

Cancer rate
* are also lower for the married population
  - up , particularly for cancers that affect the young
* differ from country to country.
* run high in poor communities because of living conditions and lifestyles.
* soar as a result of radiation in the atmosphere.
* vary enormously by age
  - with age, acculturation and location

Crime rate
* are among the lowest in the world while the standard of living is among the highest
  - world, and continue to decline
  - crude indicators of the amount of law-breaking in society
  - low in foreign countries
  - rates
* drop when prostitution is brought to a setting where it is monitored
  - the economy is doing well
* increase as one moves east to west.
* reflect the risk of becoming the victim of a crime.
* vary by urbanization.

Crude rate
* are simply the ratio of mortality to population for any given year
  - total deaths to total population for any given year
* is number of cases over population at risk.