Answer:
Explanation:
Secondary energy resources are those which do not occur naturally but which are obtained from one or more of the primary energy resources. Example: Petrol or gasoline, electrical energy from coal burning, hydrogen obtained by electrolysis of water etc. Non-commercial source of energy: Firewood, cow dung , and vegetable wastes.
The right option is; c. a salinity of less than 1%
Freshwater biomes have a salinity of less than 1%
The freshwater biome is a large community of plant and animals that live in water bodies with a salinity of less than 1%. Fresh water biomes include streams, rivers, ponds, lakes, and some wetlands. The fresh water biomes cover about 20% of the earth and they contain several species of fish and animals such as frogs, crocodiles and turtles.
The scientists will use Relative dating. It is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.
