How are decomposers positioned in a food web? a they are connected to all levels. b they are secondary consumers. c they are primary consumers. d they are autotrophs.

The answer is A, they are connected to all levels.

Decomposers in a food web, such as bacteria or fungi, mainly get their nutrient by decomposing dead organic matter to release carbon dioxide (when they respire)to the air for producers (which are mainly plants).

The following basic food chain (which forms food web when many of these are connected) may help you understand better:

Producer→primary consumer→secondary consumer→tertiary consumer

Since all levels in a food web is formed from organic matter (including plants and animals), decomposers feed on them to get their nutrient, so they're actually connect to all levels.

B is not correct because secondary consumers are the carnivores, which are animals that consume other animals for food and nutrient.

C is not correct because primary consumers are herbivores, which are animals that consume plants (or producers) for food.

D is not correct because autotrophs are organisms that make their own food by themselves, which are usually by photosynthesis (the process to make glucose from light energy). They're usually green plants, and the "producers" from a food web.

the sphincter muscles at the end of the digestive tract is the anus.

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.