1. Answer;
A. energy flows in one direction and nutrients recycle.
Explanation;
-The movements of energy and nutrients through living systems are different because the energy flows in one direction and nutrients recycle.
-Energy is transferred between organisms in one direction in a food chain, but that interconnected food chains make a food web.
-Most ecosystems get their energy from the Sun. Producers can use sunlight to make usable energy by converting it into chemical energy or food. Consumers get some of that energy when they eat producers, they pass some of the energy to other consumers when they are fed on.
2. Answer;
Nitrogen fixation.
Nitrogen fixation depends on bacteria.
Explanation;
Nitrogen fixation is the process by which nitrogen is taken from its stable gas form (N2) in air and then converted into other nitrogen compounds (such as ammonia, nitrate and nitrogen dioxide) useful for other chemical processes.
-The nitrogen fixing bacteria are microorganism capable of converting atmospheric nitrogen into forms usable by plants. They include the free-living bacteria, which includes cyanobacteria, azotobacter etc. and others such as mutualistic bacteria such as Rhizobium.