B. are more difficult to control than point sources. This is because A. is wrong (point source), and C. is wrong, because it doesn't necessarily cost less or more to identify the sources. D. may be right, as non point sources are natural, such as snow melts or rain.
<span>The correct answer is option D.An ecosystem consists of a population of organisms and its physical environment, and a population is made up of many different communities of organisms. An ecosystem is a bilogical system of populations and environment. And a population consists many communities and finally the communities are nade up of organisms.</span>
The correct answer is option C- they absorb sunlight and convert into chemical energy
- Algae, cyanobacteria and plants have one common characteristic that they prepare their own food. All of them contain a pigment called “chlorophyll”.
- Chlorophyll is a green color pigment which is required for the preparation of food during photosynthesis. It absorbs sunlight and converts into to chemical energy which is utilized by these organisms to perform.