Most of the earth's oxygen occurs in the form of minerals in the crust and mantle. the oxygen that is available in the atmosphere is used primarily by plants, animals, and bacteria to perform cellular respiration. why is running out of oxygen still not a real concern?

Environmental differences within ecosystems are generally caused by

Which of the following is an example of competition that could be found in a forest? question 14 options: deer eat berries and their droppings seed new areas creating more berry bushes two fox populations utilize the same rabbit population as their main food source two hawk populations utilize the same scorpion population as their main food source lack of sunlight due to changes in the seasons restricts the growth of certain plants

You are given an electron micrograph of a bacterial cell. in the micrograph you can clearly see three thin layers of different densities surrounding the cell. based on the micrograph, you can infer that this cell is and would appear after application of the gram stain procedure. gram-negative / pink gram-positive / purple gram-positive / pink gram-negative / purple