they have no symbiotic realships
Grazing increases root production. This could only be described as symbiosis in a very loose sense. Generally symbiotic relationships are much more dependant ...such as the termite and its gut bacteria or to a lesser degree the mutualism of an anenome and a clown fish.
Joseph Black discovered carbon dioxide (CO2).
The relationship is called parasitism. The cowbirds raid the other bird's nest and lay their eggs there. The other bird has to migrate to another tree to build a new nest.
the wadjabirri black bean
Black holes are believed to emit something called Hawking radiation.
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black widows
The spider you are describing could be a black widow spider. Black widows are known for their sleek black bodies and long, thin legs that give them a distinct appearance. They also have a red or orange hourglass-shaped marking on their abdomen.
here are lots but some are: Black widows , Brown recluse. lots mainly look on the website discovery.ca
You are probably defining a false black widow.
Only black widows have hourglasses on their backs... You should probably be careful
Symbiotic relationships are usually referred to as "give and take" but this is not always the case, whilst some may be beneficial eg. mutalistic, commensalistic others are not eg. parasitism. The isopod falls into the parasitic category where one species benefits and the other does not.
Plants make and propagate with seeds. It isn't a symbiotic relationship since that is inter-species. Many plants have symbiotic relationships with insects (bees and flowers). link on symbiosis: http://www.answers.com/topic/symbiosis?cat=health
The black spider that resembles a black widow without the red hourglass marking is likely the false black widow spider (Steatoda grossa or Steatoda nobilis). They are similar in appearance to black widows but lack the distinctive red hourglass marking. These spiders are not as venomous as black widows but can still deliver a painful bite.
It sounds like you may be describing a black widow spider. Black widows are shiny black with a red hourglass shape on their abdomen. They are venomous and can be found in dark, secluded areas in and around homes. If you suspect you have black widows in your home, it's best to contact a pest control professional for safe removal.
Symbiotic.
it is a symbiotic relationship