Answer:
The correct answer is - warning system.
Explanation:
Warning systems are a type of system that could be technical or biological in nature that can help in assessing or inform about the possible danger or change in a particular setting such as ecosystem, weather, water quality, and many others. It helps in avoiding such threats before occurring or become serious threats.
Certain biological species that live or require a particular set of conditions for their survival and reproduction can act as a biological warning system for water pollution, air pollution.
Answer:
it allows only some materials to pass through and leave the cell.
Answer:
D. Cellular respiration releases oxygen and photosynthesis releases carbon dioxide
Number 1 is C
And im not sure about the rest :(
Answer:
I've been warning people about this user as well, don't enter that link >:I
They think they are sneaky with there like 1000 profiles, what a fool they are, if you have the same pic people will instantly know!!