B. Subgroups
<span>When constructing a dichotomous key, the first step is to look at the group of objects or organisms and separate them into two groups based on a single distinguishing characteristic. Then continue to separate each of the groups until each object has its own separate set of characteristics.</span>
Answer:
Renewable energy resource as an obstacles for the growth of migratory salmon populations: It is now believed that the reduce access to spawning grounds and nursery areas, leading to a decrease in migratory fish populations is due to the dam structures of large storage-type schemes, which can create great obstacles for the movement of migratory fish species.
Explanation:
- Storage-type schemes ( big dams) can significantly change the downstream flow regime,and may also alter water temperature and quality, and even make it inhabitable for fish to live.
- As the storage of water can be linked with high evaporative losses, which in turn results in high life cycle water footprints compared to other sources of electricity.
<u>Run-of-river (ROR) schemes are HEP schemes: </u>
They operate without water storage, using the flow within a river channel.They are ecologically friendly and do not disturb the natural mechanism for the migrating salmons.
Working Principle:
They are normally used to regulate water levels, which allows a proportion or part of flow to be diverted down a secondary channel to a turbine before it is returned to the main channel further downstream.
There are some modern turbine types used in ROR HEP(hydroelectric power) schemes, which are also designed to allow fish to pass through the system unharmed if the fish do pass through the intake screens.
It was 77.27% as the <span>labor force participation rate in 2000</span>
