How can energy be supplied to chemical reactions in living systems?

24. They supply cells with nitrogen.
25. Cellulose
26. Protein
27. They help bring about chemical reactions.
28. hydrogen bonds
29. starch
30. It has all nine of the essential amino acids.

answer:

hydrogen and fuel cells can be used in a broad range of applications. these range from powering buildings, cars, trucks, to portable electronic devices and backup power systems

explanation:

C = glucose

Explanation:

Glucose is break down and produce the energy.

Their are two process through which glucose is break down.

2.Anaerobic respiration

Aerobic respiration

It is the breakdown of glucose molecule in the presence of oxygen to yield large amount of energy. Water and carbon dioxide are also produced as a byproduct.

Glucose + oxygen → carbon dioxide + water + 38ATP

Anaerobic Respiration

It is the breakdown of glucose molecule in the absence of oxygen and produce small amount of energy. Alcohol or lactic acid and carbon dioxide are also produced as byproducts.  

Glucose→ lactic acid/alcohol + 2ATP + carbon dioxide

This process use respiratory electron transport chain as electron acceptor instead of oxygen. It is mostly occur in prokaryotes. Its main advantage is that it produce energy (ATP) very quickly as compared to aerobic respiration.  

Contractile

Explanation:

B. Enzymes act as a biological catalyst as they significantly speed up the rate of virtually all chemical reactions that take place within cells. Enzymes are highly specific and each enzyme will only support one type of reaction. Enzymes are a form of proteins. Therefore, C is incorrect. They definitely don't supply energy to start a chemical reaction.

I believe it is C, because they lower the need for energy but don’t provide it

The correct options are as follows:
24. THEY SUPPLY CELL WITH NITROGEN.
Lipid is one of the classes of food that are very essential for humans' health. There are different types of lipids and they have a lot of vital roles which they play in the human system. The functions of lipids include the following: they form a structural part of the cell membranes, they provide cells with energy, they carry fat soluble vitamins to the body cells, they keep the body warm, they serve as shock absorber to some organs in the body, etc.
Lipids do not supply the body cells with nitrogen.

25. CELLULOSE.
There are different types of carbohydrate, some are found in animals only, some are found in plants only while some are found in both plants and animals. Cellulose is a type of carbohydrate that is found only in plants. Paper is usually made from wood pulp, which is derived from plants, thus the type of carbohydrate found in paper is cellulose.

26. PROTEINS.
Protein is one of the classes of food, which are very essential for human health. We have basically twenty different types of proteins and these proteins are formed from amino acids.Some of the proteins are described as non essential because we do not need to consume them in our food, they are already present in adequate amount in our bodies. Some are describe as essential because we need to eat them in our food. Proteins are the ones that are responsible for building new tissues and repairing injured ones. They also serves as enzymes, which speed up the rate of biochemical reactions in our bodies.

27. THEY HELP BRING ABOUT CHEMICAL REACTIONS
Enzymes are biological catalysts which speed up the rate of biochemical reactions in our body. Each biochemical reaction has its own specific enzymes. Without enzymes the body will not be able to digest eaten food in record time and this will lead to cell death and the eventual death of the concerned organism. 

28. HYDROGEN BOND
DNA belongs to the class of nucleic acids, nucleic acids are made up of many nucleotide which are joined together. A nucleotide is made up of phosphate, nitrogenous bases and a five carbon sugar molecule. A strand of DNA is made up of nucleotides that are joined together by phosphodiester bonds. A DNA molecule is made up of two strands of nucleotides that are twisted to form a double helix, it is the hydrogen bonds that hold the two strands together.

29. STARCH.
Plastids refers to the small organelles that are found inside the plant cytoplasm which contains food molecules. Plants typically store starch molecules inside the plastids. This is because, the food molecules that are manufactured by plants through photosynthesis are normally store in plants in form of starch. Animals and humans use this starch as food in order to produce energy for body use.

30. IT HAS ALL NINE OF THE ESSENTIAL AMINO ACIDS.
As I mentioned earlier, there are some amino acids which are considered to be essential proteins, we must consume these proteins in our foods because our bodies can not synthesize them. The protein are nine in number and they are: valine, tryptophan, phenylalanine, threonine, methionine, leucine, isoleucine, lysine and histidine. 
A complete protein is a protein that consist of all these nine proteins.