Answer:
The answer is C, persistence.
Fuel cells can make an electricity from a simple electrochemical
reaction in which oxygen and hydrogen combine to form water. There are several
different types of fuel cell but they are all based around a central design
which consists of two electrodes, a negative anode and a positive cathode.
These are separated by a solid or liquid electrolyte that carries electrically
charged particles between the two electrodes. A catalyst, such as platinum, is
often used to speed up the reactions at the electrodes. Fuel cells are
classified according to the nature of the electrolyte. Every type needs
particular materials and fuels and is suitable for any applications. The
article below uses the proton exchange membrane fuel cell to illustrate the
science and technology behind the fuel cell concept but the characteristics and
applications of the other main designs are also discussed. Proton Exchange Membrane Fuel Cells (PEMFC)
The hydrogen ions permeate across the electrolyte to the
cathode, while the electrons flow through an external circuit and provide
power. Oxygen, in the form of air, is supplied to the cathode and this combines
with the electrons and the hydrogen ions to produce water. These reactions at
the electrodes are as follows:
Anode: 2H24H+ + 4e-
Cathode: O2 + 4H+ + 4e- 2H2O
Overall: 2H2 + O22H2O + energy
PEM cells operate at a temperature of around 80°C. At this
low temperature the electrochemical reactions would normally occur very slowly
so they are catalysed by a thin layer of platinum on each electrode.
The Calvin cycle (also known as the Calvin–Benson cycle) is the set of chemical reactions that take place in chloroplasts during photosynthesis. The cycle is light-independent because it takes place after the energy has been captured from sunlight.
About 96% with added things like al the vitamins and minerals. And the flavoring ect.
Answer:
A. Chipmunks sleeping underground through the winter
Explanation:
A seasonal change in the behavior of a living organism is a change that occurs every year at a particular time. The reasons for the occurrence of such changes are so that the organism has advantage in survival in the environment. In this case we have the chipmunk that sleeps underground through the winter. We have an animal which exhibit a seasonal change every year, during the winter period. The reason for this is that the chipmunks have very quick metabolism, so if they are active during the winter they will starve because of lack of food. Instead, the chipmunks have evolved to hibernate during the winter, thus slowing down the work of their hurt during the winter and sleep, until the spring comes.
