### substance | sealant:

Dental sealant
* act as a barrier, protecting the teeth against decay-causing bacteria.
* are a vital component of caries prevention
  - simple to apply, requiring no anesthetic
* can only provide their best protection when they are fully intact
  - provide a further layer of protection against cavities
* consist of a plastic material that is applied to the tooth enamel.
* protect children's teeth and help prevent cavities.
* provide specific protection against that kind of cavity.

Sealer
* also offer resistance to rain, sun, freezing temperatures, petroleum, and deicing salts.
* form hard, slick surfaces that have the potential for bond failure once the paste dries.
* is officials.
* often use sharpened steel hooks to drag the creatures on board their vessels.

### substance | sealer:

Caulk
* also bond better and are likely to stay put longer when applied during warmer weather.
* can be difficult to keep in vertical joints and on a variety of substrates
  - deteriorate over time allowing water to leak into walls and floors
* comes in many colors to match the existing surface color.
* cracks around windows and doors to keep the heat out and the cool in
  - prevent water from seeping inside
  - windows, doors, and fascia boards
  - that ants are using to enter the home
  - with a caulking material prior to applying water repellent
* is sealer
* is the material that comes in a tube and is forced out with a caulking gun
  - putty that seals between the window frame and the house
  - used around outside window and door frames, and to fill outside wall and foundation cracks
* is used to fill hairline cracks
  - waterproof, insulate and seal

### substance:

Semen
* comes from different sources.
* comes from several different sources
* contains bicarbonate, ascorbic and citric acids, water, enzymes, fructose and sugar
  - materials
* has characteristics.
* includes acrosomes
  - cell membranes
  - cytoplasm
  - flagella
  - nuclei
  - plasma membranes
  - sections
  - sperm
  - vacuoles
* is humour
* moves through the urethra and comes out of the hole at the tip of the penis.
* travelss through urethras.
+ Penis, Ejaculation: Anatomy of the male reproductive system
  * When a man has sexual intercourse with a woman, he places his erect penis within her vagina and moves it in and out. The vagina is warm and soft, and it places pressure on the man's penis. This makes the man have an orgasm and ejaculate. During orgasm, muscles push semen from the penis and into the vagina. Semen moves through the urethra and comes out of the hole at the tip of the penis.

### substance:

Shale
* Most shale contains salt.
* Some shale contains coal
  - crystal
  - minerals
  - sulfide minerals
  - shales are very soft and fall apart in water, others can be quite hard
* are often rich in oil and burn readily
  - one of the more important common constituents of rocks in log analysis
* break easily along their layering, especially along weathered surfaces.
* can adsorb the series radionuclides.
* can exist as grains or nodules in the formation matrix
  - in the form of laminae between which are layers of sand
* contain the lion's share of earth history that is recorded in sedimentary rocks.
* contains clay and is in small, thin layers
* have permeabilities of the order of a few millidarcies.
* is clay that has been converted into rock masses
  - important because it contains the products of former life on earth, and their hydrocarbons
  - soft and porous
* represent deeper marine environments and sandstone represents shoreline environment.
* weather very easily to form mud and clay.