Answer:b
Explanation: b is correct
Over long periods of time, living things have gradually altered as the conditions around them change. A species' strongest traits are passed from one generation to the next. This is what evolution is, the process of gradual change.
The number of producers is more than consumers and top carnivores in ecosystem. for example:- in the food chain of grass--goat--man,atleast 90% of energy is pasted to other level and 10% will be stored at that level it self.
grass goat man
50/100 40/80 30/60.
as we human beings depend on plants and animals for our food for our whole life we need atleast 100 numbers of small plants for one week.
Pure water freezes at 32 degrees Fahrenheit, and at 0 degrees Celsius.
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