### suitability | fitness:

Aerobic fitness
* can also ease the burden of pregnancy.
* improves when students exercise in the aerobic training zone.
* indicates the capability to perform prolonged work.
* is critical for children
  - dependent upon age and sex and it can be improved by training
  - maintained with stationary cycling
  - related to health
  - required for sustained periods of hard work and vigorous athletic activity
* is the capacity to maintain vigorous exercise without becoming exhausted
  - single most important health indicator
* requires the heart and lungs to work harder to deliver oxygen to the muscles.

Cardiovascular fitness
* improves the cardiovascular system through exercise.
* is important, too, as heart disease is one of the major causes of death
  - stressed as the key to physical fitness
  - the key to good health
  - very important, especially in becoming and staying lean

Evolutionary fitness
* is measured in terms of reproductive success.
* measure of physical health.

Habitability
* also determines the base population growth rate for a colony at that system.
* general term which connotes a level of environmental acceptability.
* is an indication of environmental quality as perceived by the occupants of buildings
  - what allows a tenant to escrow rent for that purpose
* word to which students attatch significant meaning.

Individual fitness
* decreases as population density decreases
  - increases
* has a direct impact on a unit's ability to operate.

Mental fitness
* is an important attribute and goes hand in hand with physical fitness.
* is just as important a factor in overall health as is physical well-being
  - as physical fitness
  - necessary for total fitness
* whole diffrent discusion.

Metabolic fitness
* improves total metabolism through exercise.
* means having normal values for blood pressure, blood cholesterol and blood sugar.

Muscular fitness
* combination of strength, endurance and flexibility.
* consists of both strength and endurance.
* includes strength, muscle endurance, and flexibility.

Total fitness
* fundamental prerequisite to safe practices in gymnastics.
* is more than being able to play sports
  - losing weight and shaping muscle
  - the focus to prepare youths for their sport competition

Sulfide
* Most sulfides contain minerals.
* Some sulfides are produced by bones
  - whale bones
* Some sulfides have properties
  - resistance
  - possess semi-metallic character and have potentially valuable electronic properties
* Some sulfides react with other substances
* are chemical compounds
  - quite rare
* are typically opaque and characteristically colored with distinctive streaks
  - opaque, colored with distinctive streaks
* can cause effects from eye irritation to suffocation.
* cause asthmatic attacks, breathing difficulties, allergies and can cause death.
* controls on mercury speciation and the bioavailability in sediment pore waters.
* have a characteristic smell, especially as samples are fractured, reacting, or powdered.
* increase corrosion in that setting.
* occurs in many well water supplies and sometimes in formed in lakes or surface waters.
* release highly toxic hydrogen sulfide gas during toning or when treated with acid.
* tend to be soft, brittle minerals with a high specific gravity.

### sulfide:

Ammonium sulfide
* is added to the preceding precipitate and the sulfides dissolve.
  * very toxic chemical. It is also explosive and highly flammable. It is added to cigarettes

Antimony sulfide
* is used in matches.
+ Antimony, Uses: Chemical elements :: Semimetals
  * Another use is in a catalyst for making some plastics. Antimony is used as a dopant in electronics. Some antimony compounds were used as medicines to kill protozoans. The antimony pill was a chunk of antimony that was supposed to heal diseases. It is used in medicines for pets. Antimony sulfide is used in matches.