A) single loop
Fish have a two-chambered heart in which a single-loop circulatory pattern takes blood from the heart to the gills and then to the body.
Biodiversity depends on a species' ability to reproduce itself. If a species cannot reproduce then it will die out. This depends on the climatic conditions of the region. If there is a natural disaster for example, it will affect a species' ability to reproduce. This reduces the number of diverse species on earth. Biodiversity is the recognised variety of different types of life found on the earth. It also measures the variety of number and variety of plants, animals and other organisms found in different ecosystems.
The answer is; YES they do
Photosynthesis is important in taking carbon from the atmosphere . This is why forest are great carbon sinks because they sequester carbon from the atmosphere. Cellular respiration, on the other hand, is the opposite of photosynthesis. It increases the levels of carbon in the atmosphere by breaking down carbon-based foods to carbon dioxide.