Organisms may contain up to five levels of organization within their bodies. which level of organization is shown by the liver?
tissue
organ
organism
organ system

The correct answer is organ.

Explanation:

The liver is an organ because it is made up of tissues (group of cells) with specific functions and acts in conjunction with other organs to form a system, which together with other systems work in coordination for the proper functioning of an organism.

photosynthesis makes the glucose that is used in cellular respiration to make atp. the glucose is then turned back into carbon dioxide, which is used in photosynthesis. while water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.