Calorie is the term used to measure the amount of energy in a food or a drink.

c. Calories

Carbohydrates are known as the major energy source for most organisms.

c. carbohydrates

Minerals are inorganic elements or substances that are formed naturally in the Earth.

B. minerals

Mechanical digestion begins when the food is chewed inside the mouth.

C. mouth

The enzyme amylase is found in the saliva. It helps break down starches into sugar.

C. amylase

A series of wave-like contractions along the smooth muscles of the esophagus is known as peristalsis.

B. peristalsis

According to the graph, the urea in the urine has increased after several days of fasting. The first day of fasting has produced 90 mg/dL of urea in urine, whereas the third day of fasting has produced 120 mg/dL of urea in urine.

C. increases for the first few days of fasting

The site where absorption of most nutrients takes place is in the small intestine.

D. through the villi of the small intestine

Each kidney consists of millions of nephrons. A nephron is the basic structural unit found in the kidney.

A. nephron

The urine is carried outside the body through a tube called urethra.

c. Urethra

The food that we eat provides us with energy and nutrients which are used by the body for its growth, maintenance, and repair.

Carbohydrates are known as the major energy source for most organisms.

Here are the three important benefits of proteins in our body:

1. Getting protein in the body helps build and repair cells and tissues.
2. Proteins help regulate the body’s physiological processes and ensure transport of nutrients and other substances in the body.
3. Proteins are the sources of essential amino acids.

The new food pyramid shows us that there are six categories of foods. These categories include grains, vegetables, fruits, sugars, salts, meat and beans, and fats. The new food pyramid is also color-coded. The yellow bar represents food that should be consumed in the small amounts. These are fats, sugars, and salt. The orange bar represents the grains and the green bar represents vegetables. Grains and vegetables are foods that should be consumed in large amounts. The red bar represents fruits, whereas the blue bar represents milk and other dairy products. The purple bar represents the meat and beans category.

Mechanical digestion of food materials starts with the mouth and after which it will be swallowed down using the action of the tongue and throat as the muscles pushed the bolus (broken food material) into the pharynx to the esophagus. A flap of connective tissue called the *epiglottis* covers the opening of the trachea from the pharynx, preventing the food to enter the respiratory system and the blocks the incoming air.

**Digestion** is a process in which an organism obtains nutrients and energy through the breakdown of the food we intake. This process happens in our digestive system which is composed of the following organs: mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

Together with these main organs present in the system, accessory structures are also present to help in digestion. These structures including the salivary glands, pancreas, and liver secrete *digestive enzymes* that efficiently break down food materials via **chemical digestion**.

**Digestion** is a process in which an organism obtains nutrients and energy through the breakdown of the food we intake. This process happens in our digestive system and comprises the following organs: mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

Digestion is divided into two parts: **mechanical digestion** and **chemical digestion**.

1. **Mechanical digestion** – this is the physical process of breaking down complex food materials into smaller ones. It happens in the mouth, as the teeth cut, and tear the food that we intake.

2. **Chemical digestion** – the process in which digestive enzymes begin to break down small food pieces into their molecular form which the body can absorb. Chemical digestion also happens in the mouth through the action of *saliva*, but most of the action happens in the stomach and the small intestine.

Hydrochloric acid is the body’s primary digestive fluid. It activates the pepsin, which is an enzyme that acts to breakdown protein into small peptides. Both hydrochloric acid and pepsin work together in the process of protein digestion.

**Chemical digestion** is the process in which digestive enzymes begin to break down small food pieces into their molecular form which the body can absorb. Chemical digestion also happens in the mouth through the action of saliva, but most of the action happens in the stomach and intestine.

The stomach lining is composed of numerous microscopic glands that secret various substances including hormones and enzymes that aid in chemical digestion. Two of the known substances present in the stomach are **hydrochloric acid** and **pepsin**. **Hydrochloric acid** activates the enzyme pepsin, and together they work in the break down of protein materials in the stomach.

The **villi** are epithelial folds that form tiny projects in the wall of the small intestine. It forms an extension on the lumen of the intestine and plays an important role to increase the surface area of the organ. These villi are composed **microvilli** which are part of the intestinal cells itself that function to increase the absorption of nutrients in the organ.

**Digestion** is a process in which an organism obtains nutrients and energy through the breakdown of the food we intake. This process happens in our digestive system and comprises the following organs: mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The **large intestine** specifically is where reabsorption of water happens. Water is absorbed efficiently and quickly in this area of the GI tract.

The stomach lining is composed of numerous microscopic glands that secret various substances including hormones, acids, and enzymes that aid in chemical digestion. The stomach effectively and efficiently breaks down food materials because of these substances, However, in rare cases, a bacterium called ***Helicobacter pylori*** invades the stomach and creates a hole in the lining thus resulting in an infection called **peptic ulcer**.

The **kidney** is the main organ of the excretory system and it is found on either side of the spinal cord near the lower area. This organ is composed of many functional units called nephrons which function to filter the blood and reabsorb the necessary nutrients.

The materials that are filtered from the blood are jointly referred to as **filtrate** and it is composed of the following materials:

1. Water
2. Urea
3. Amino acids (creatinine)
4. Salts
5. Glucose
6. Some vitamins.

Those that remain in the blood are the following: proteins, blood cells, and platelets. These materials remain because they are too large to pass through the walls of capillaries.

**Reabsorption** is the process in which solute materials and water are brought back into the blood circulation for the body to use. The process is named *reabsorption* as it is the second time these materials are being absorbed by the body. In the excretory system, reabsorption happens in the Bowman’s capsule. A number of substances including water and biomolecules like fats, amino acids, and glucose are being reabsorbed by the capillaries.

The activities in the kidney are regulated by the hormones and the blood composition or content. For example, once the body detects there is only a little water content in the blood, the body produces hormones that would signal the kidneys to retain water in order to avoid dehydration.

**Digestion** is a process in which an organism obtains nutrients and energy through the breakdown of the food we intake. This process happens in our digestive system and comprises the following organs: mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

The **small intestine** is where most of the chemical digestion and absorption of nutrients happens. Therefore, an individual without a *small intestine* cannot eventually survive because there will be an incomplete digestion process, and important nutrients will not be able to be absorbed by the body.

does not provide all the nutrients/vitamins the body needs for necessary body function/regulation.

please see explanation

**Pancreatic juice** is created in the pancreas of an individual and it is released from the pancreas to the small intestine to aid in the digestion process. In the question presented, the experiment wanted to know the activity of the pancreatic juice on the various substances present in the small intestine. These substances now act as the *dependent variables*.

These variables are the following: **Protein, fat, and hydrochloric acid**.

The presence of protein produces an equal percentage of bicarbonate and digestive enzymes in the pancreatic juice. The pancreatic secretion contains 50 percent of bicarbonate and another 50 percent of digestive enzymes.

The presence of fat in the small intestine has caused the percentage of digestive enzymes to increase by 80 percent, whereas the percentage of bicarbonate has decreased to 20 percent.

Once we consume foods, the digestive system works in breaking down the food into smaller or simpler components that the body can absorb and use in order to perform cellular processes. Since most foods contain starch, the saliva contains an enzyme called amylase. It helps break down starches into sugar.

When iodine is added to a starch, a blue color will appear. Once the starch is broken down, the blue color disappears. To determine whether the starch digestion begins in the mouth, this experiment can be done:

Materials:
a. beakers
b. starch solution
c. iodine
d. saliva
e. spoon (for mixing)

Steps:
1. Pour the equal amounts of starch solution in two beakers. Label it with beaker A and beaker B.
2. Add saliva in beaker B. Leave the beakers and wait for 30 minutes.
3. Pour iodine in both beaker A and B. Observe the changes.
4. Mix the solution with a spoon. Again, observe any changes in the solution.
5. Repeat steps 3 and 4. Wait until both solutions have turned dark blue.
6. Set the two beakers aside and wait for 30 minutes.
6. Observe any changes in the color of the solution.
7. Compare the results.

The results will show that the solution in beaker A will remain blue in color. This indicates that there is a presence of starch, hence, it is not broken down. On the other hand, the solution in beaker B has turned white and the blue color has disappeared. The disappearance of the blue color indicates that the starch has already broken down due to the enzymes found in the saliva.

Since most foods contain starch, the saliva contains an enzyme called amylase. It helps break down starches into sugar. To determine whether the digestion of starch begins in the mouth, prepare two beakers with equal amounts of starch solution. Add saliva in one of the beakers. After 30 minutes, put iodine in both beakers. When iodine is added to a starch, a blue color will appear. Once the starch is broken down, the blue color disappears.

Foods that are rich in complex carbohydrates (starches from grains, vegetables, and fruits) provide high energy and fiber. The energy is usually stored in the liver and skeletal muscles for further use, while fiber aids in digestion. It helps the muscles move food and water efficiently in the digestive and excretory systems.

A fiber-rich diet, which is packed with complex carbohydrates, is healthier when compared to an American diet because it does not contain large portions of fat which increases the risk of heart disease, obesity, or high blood pressure. It promotes a better digestion and reduces cholesterol in the body.

Two things may occur when all the bacteria in the body are killed:

1. If good bacteria, which live in the digestive system to aid in digestion, are destroyed, indigestion may occur and it might lead to decreased bowel movements.

2. The good microbes living inside our bodies are competing with harmful pathogens. They help the immune system fight diseases. If these good microbes are killed, you are prone to acquire diseases due to the weakened immune system.

**Digestion** is a process in which an organism obtains nutrients and energy through the breakdown of the food we intake. This process happens in our digestive system and comprises the following organs: mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

**Mechanical digestion** is a type of digestion process in which the food is physically broken down from large pieces to smaller ones through the use of our mouth via chewing. Hence, prolonged chewing will eventually cause the food materials to be smaller–where carbohydrates and proteins will be easily digested in the stomach.

If the kidneys stop working or fail to fulfill some of its functions, the whole body will suffer. There will be a buildup of fluid in the body which will result in the swelling of some body parts. The blood will not function properly since it would not be filtered and cleansed from toxins and wastes. As a result, the body becomes weak and this condition may lead to seizures, coma, and even death.