### herbicide:

Contact herbicide
* Most contact herbicides become more active as temperatures increase.
* are most effective against annual weeds
  - on annuals
* destroy only plant tissue that contacts the herbicide.
* kill only the part of the plant they touch
  - or injure only that part of the plant with which they come in contact
* provide the best control when applied to small weeds.

Nonselective herbicide
* are toxic to all plants.
* can injure or kill any vegetation they come into contact with.
* kill or injure almost all plants.
* require a wide safety zone to prevent crop damage.

Residual herbicide
* Most residual herbicides work best when incorporated into the soil by rainfall or irrigation.
* continue to provide significant improvements to glyphosate-based weed control.
* pose a risk to the environment if applied to waterlogged soils.
* work best if applied to moist soil.

Selective herbicide
* can control the stems but often the haustoria escapes.
* is more toxic to some plants than others when used at proper concentrations.
* kill broadleaf plants but spare conifers, giving trees the advantage
  - certain targets while leaving the desired crop relatively unharmed
  - some plants with little or no injury to other plants

Several herbicide
* are effective against tansy ragwort
  - for home use for most weeds or grasses
  - in eradicating poison ivy
  - registered in pasture, rangeland and noncrop areas to control musk thistle
* can control broadleaf weeds and grasses after alfalfa emergence.
* have activity on hemp, although none are registered for that use
  - some effectiveness in controlling nutsedge, but none are really good
* provide good to excellent control of thistle rosettes.

Systemic herbicide
* Most systemic herbicides perform better under conditions that are ideal for weed growth.
* are absorbed and move within the plant to the site of action
  - capable of killing the entire plant
* can cause severe damage if they contact the asparagus plants.
* kills every part of the weed from the roots to the tips of the leaves.
* move into the weeds' roots with the weeds' carbohydrate building blocks.
* tend to act more slowly than contact herbicides.

### herbivores:

Arctic hare
* Most arctic hares feed on plants
  - woody plants
* Most arctic hares have bright white coats
  - claws
  - eyesights
  - good eyesights
  - long claws
* Some arctic hares eat animals
  - arctic willows
  - moss
  - small animals
  - feed on bark
* Some arctic hares have ears
  - ranges
  - years
* are herbivores
  - nocturnal
  - the largest species of hare found in North America
* have a bit of black on the tips of their ears.
* have bright white coats to blend with their snowy surroundings
  - short ears while hare outside of Arctic areas have long ears
  - small home ranges and tend to follow familiar paths as they forage

Saiga antelope
* Most saiga antelopes have habitats
  - legs
  - short tails
  - thin legs
* Some saiga antelopes die from bacterial infection
* are a migratory species that inhabit the steppes of central Asia
  - regular grazers and they readily feed on herbs, shrubs, lichens, and grasses
  - valued for their fur, meat, and horns
* drink from a lake outside Almaty, Kazakhstan.
* has long, thin legs but is similar in size to a sheep.

Terrestrial turtle
* Most terrestrial turtles are herbivores
  - eat flowers
  - live in areas
* need humidity
  - lower humidity
* tend to eat insects and plants, especially mushrooms and berries.

### herbivorous:

Leopard tortoise
* Some leopard tortoises become pets.
* Some leopard tortoises have carapaces
  - homes
* are herbivorous.