Which of these is characteristic of the photic zone of a freshwater biome? the presence of algaerelatively cool waterelatively stable water temperaturedead organic matterlow oxygen level

The correct option is this: THE PRESENCE OF ALGAE.

Explanation:

Freshwater biome refers to bodies of water that contain relatively small amount of salt (typically about 1%) in comparison with the ocean. Examples of freshwater include: lake, ponds, streams, rivers, etc.

The freshwater biome is usually divided into different zones depending on the water depth and the amount of sunlight that is available at each depth.

The photic zone is the first layer of the water body, which receives direct sunlight. The large quantity of sunlight receive by this zone make it possible for photosynthesis to take place in the region.

This zone is very important because it made up of plants such as algae and phytoplankton, which are primary producers of the biome; the rest of the living creature in the water bodies depend on these plants to survive.  

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.