<span>The answer is d. front. A front is the narrow region between two air masses of different densities. The interaction of the air masses cause the mass that is less dense to rise. Once air rises it cools and condenses to form clouds and eventually leads to precipitation. Using cold fronts as an example, the denser mass of cold air forces the lighter warm air to rise. </span>
Answer:
Good examples include cyanobacteria and green and purple sulfur bacteria. Producers are organisms that are capable of producing their own food using water, light and other chemicals. They are also known as autotrophs.
Explanation:
Answer: D)organisms that possess overall characteristics best suited to their environment
Explanation: organisms that can evolve best suited have a better chance of life for example if put a rat in the arctic it will die to the cold but a paler bear will survive.
Answer:
Active Transport
Explanation:
Active transport is the process of transport of substances from region of their lower to that of higher concentration. Since the transport occurs against the concentration gradient, it is energy requiring process and needs input of energy to occur.
In given example, liver cells transports vitamins against the concentration gradient in energy dependent manner. Therefore, it is an example of "active transport".