The correct option is D.
Both carbohydrates and fat produce energy within the cell, but the amount of energy produce by fat for each one gram of food is much more than that of carbohydrate. Fat in the food is absorbed into the body in form of triglycerides.
The spines of the cactus have several functions, which are the following:
To defend them from possible predators: inside the body of the plants there is a great deal of water; if herbivores could access it, these plants would not survive.
To provide them with shade: it is true that not much, but it is enough so that the loss of water by evaporation is minimal.
Reflect sunlight: many species have white spines.
The biosphere
(I am pretty positive thats the answer)
The term rare amino acids is misleading in some respects. It refers to all those amino acids that are not incorporated into proteins. We already got to know some of them like ornithine or citrulline that are rather common intermediates of the basic metabolism. Roughly 220 different structures are known, most of which occur in plant cells in a free state though glutamate-, oxalate- or acetyl- derivatives can also sometimes be found.
Source: https://s10.lite.msu.edu/res/msu/botonl/b_online/e20/20e.htm
Hope this helps!
