It is A. Those are all decomposers, the other answers like C are all animals. Decomposers are are biotic organisms that break down basically dead plants or animals.
Multicellular organisms do this by assigning specific roles to specific cells. This enables various cells within a larger organism to collaborate in order to preserve homeostasis. Since they are made up of just ONE type of cell, unicellular organisms do not need cell specialization to maintain homeostasis.
Answer:
Carbon cycle may be defined as a type of biogeochemical cycle that regulates the amount of carbon in nature. The carbon is released by the living animals and utilized by the plants in form of carbon dioxide.
Photosynthesis consumes the carbon dioxide to make carbohydrates where as cellular respiration releases carbon dioxide and breakdown the carbohydrate. Both these process helps in recycling of the carbon in nature and maintains the level of carbon in nature.