3. What is the main cause of acid rain? *
a. decrease in ozone levels
O b. burning of fossil fuels
c. changes in the atmosphere
O d. changes in the climate

Deer cave cannot support photosynthesis is as not enough sunlight is present. in spite of this, it still has a complex food chain. what is the energy foundation of this food chain?

Aperson with age is more likely to catch diseases that healthy people usually don’t catch.what are these infections called?

Name the organs of humanelemintary canal.