Obtaining Energy and Removing waste

Which of the following is the longest organ in the digestive system?

• Heart

• Small Intestine

• Large Intestine

• Esophagus

Answer explanation

The small intestine is the longest organ in the digestive system, measuring about 20 feet in length. In contrast, the large intestine is shorter, and the esophagus and heart are not part of the digestive system.

Which type of digestion breaks down pieces of food into small molecules?

• mechanical digestion

• peristalsis digestion

• chemical digestion

• absorption digestion

Answer explanation

Chemical digestion is the process that breaks down food into small molecules through enzymatic reactions, allowing nutrients to be absorbed. In contrast, mechanical digestion involves physical breakdown, and peristalsis is a movement, not a digestion type.

What are the steps of the digestive system in order starting with food entering the mouth?

• Food enters the MOUTH, goes down the ESOPHAGUS, enters the STOMACH, enters the LARGE INTESTINE, enters the SMALL INTESTINE, waste is removed from the body.

• Food enters the MOUTH, goes down the ESOPHAGUS, enters the STOMACH, enters the SMALL INTESTINE, enters the LARGE INTESTINE, waste is removed from the body.

• Food enters the MOUTH, enters the STOMACH, goes down the ESOPHAGUS, enters the LARGE INTESTINE, enters the SMALL INTESTINE, waste is removed from the body.

Answer explanation

The correct order of the digestive system is: food enters the MOUTH, goes down the ESOPHAGUS, enters the STOMACH, then the SMALL INTESTINE, followed by the LARGE INTESTINE, and finally, waste is removed from the body.

What is the process called where food is ground into smaller pieces by the teeth?

• Mechanical Digestion

• Chemical Digestion

• Stomach

Answer explanation

The process where food is ground into smaller pieces by the teeth is called Mechanical Digestion. This physical breakdown of food is essential for easier digestion and absorption of nutrients.

An activity like sleeping does not require energy.

• True

• False

Answer explanation

Sleeping does require energy for bodily functions like brain activity and maintaining homeostasis. Therefore, the statement is false.

Digestion begins in the mouth with chewing and ______________ beginning to break down food.

• esophagus

• stomach

• liver

• saliva

Answer explanation

Digestion begins in the mouth with chewing and saliva, which contains enzymes that start breaking down food. The esophagus, stomach, and liver are involved later in the digestive process.

When does the first step of digestion usually occur?

• when the organism discovers the food

• when the food is chewed

• when the food is swallowed

• when the nutrients are absorbed

Answer explanation

The first step of digestion occurs when the food is chewed, as this mechanical process breaks down food into smaller pieces, making it easier for enzymes to act on it during subsequent digestion stages.

Removal of waste products in the body is called ________________.

• respiration

• excretion

• circulation

• transpiration

Answer explanation

The removal of waste products from the body is known as excretion. This process is essential for maintaining homeostasis and involves organs like the kidneys and liver, which filter and eliminate waste.

Which of the following plays a role in the excretory system?

• skin

• respiratory system

• kidneys

• all of the above

Answer explanation

The skin, respiratory system, and kidneys all contribute to the excretory system. The skin excretes waste through sweat, the respiratory system removes carbon dioxide, and the kidneys filter blood to produce urine. Thus, all play a role.

Enzymes (chemicals) in your saliva help break down food while chewing. This is...

• Mechanical digestion

• Chemical digestion

Answer explanation

The enzymes in saliva break down food chemically, which is known as chemical digestion. This process involves the chemical alteration of food substances, distinguishing it from mechanical digestion, which involves physical breakdown.