CBSE Questions for Class 10 Biology Life Processes Quiz 7 - MCQExams.com

• Amylase is an enzyme that breaks down complex starch molecules into simple sugars. 
• It is found in the saliva, present in the mouth. 
• it is also released by the pancreas. Due to the presence of amylase in the saliva, it is said that the digestion process starts from the mouth itself.
• Bile juice acts on fats. HCl is not an enzyme, it is an acid. 
• Pepsin is an enzyme that helps in the digestion of proteins.

$$\textbf{Correct Option C}$$

$$\textbf{Solution}$$

$$\bullet$$ $$\textbf{Option A}$$ The digestive system is made up of the digestive tract and other organs that help the body break down and absorb food. It is a long, twisting tube that starts at the mouth and goes through the oesophagus, stomach, small intestine, large intestine and anus.

$$\bullet$$ $$\textbf{Option B}$$ The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs and blood vessels. They delivers oxygen to the cells in your body. This system also helps in removing waste gases, including carbon dioxide, from the body when you exhale.

 $$\bullet$$ $$\textbf{Option C}$$  The circulatory system is made up of blood vessels that carry blood away from and towards the heart. Arteries carry blood away from the heart and veins carry blood back to the heart. The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide.

$$\bullet$$ $$\textbf{Option D}$$ The endocrine system is a complex network of glands and organs. It uses hormones to control and coordinate your body's metabolism, energy level, reproduction, growth and development, and response to injury, stress, and mood. 

$$\bullet$$ $$\textbf{Option E}$$ The nervous system is the part of an animal's body that coordinates its behavior and transmits signals between different body areas. In vertebrates it consists of two main parts, called the central nervous system (CNS) and the peripheral nervous system (PNS). 

So, the correct option is C. 

• There are four chambers in the human heart. 
• There are two anterior chambers, the auricles which are also called the atrium, and two posterior chambers, the ventricles. 
• The auricles are the “receiving chambers” as they receive blood from different body parts. 
• The ventricles, on the other hand, are the “distributing chambers”.
  
• The ventricles are larger chambers and also have thicker muscular walls when compared to the auricles 
  

• The pancreas helps in digestion by secreting pancreatic juice in the small intestine. 
• However, the pancreas is a gland and is not a part of the alimentary canal.
• The alimentary canal is a muscular tube that extends from mouth to anus and includes the mouth, pharynx, esophagus, stomach, and intestines.

• Deoxygenated (unpurified) blood comes into the right atrium of the heart through the superior and inferior vena cava which is then passed to the right ventricle and then to the lungs by the pulmonary artery. 
• In the lungs, this blood gets oxygenated (purified) which then goes into the left atrial chamber of the heart from which blood is passed to the aorta and then circulated to the whole body.

$$\textbf{Correct answer: D}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ Chocolate is one of the most common agents responsible for tooth decay. A higher intake of it is never beneficial for the teeth.

$$\textbf{Option (B):}$$ 

$$\bullet$$ Sweets are another cause of tooth decay. The artificial sugar that is used in most sweets is the reason behind this.

$$\bullet$$ This artificial sugar breaks down in the mouth causing the effect on tooth enamel.

$$\textbf{Option (C):}$$ 

$$\bullet$$ Cold drinks contain some sugar supplements that are called artificial sweeteners.

$$\bullet$$ Such sugar residue was always possible for causing tooth decay when the sugar broke down in the mouth.

$$\textbf{Option (D):}$$ 

$$\bullet$$ All the different food listed here when consumed can cause tooth decay.

$$\bullet$$ The main reason behind this is artificial sweeteners. All of them have artificial sugar that can directly affect the tooth enamel.

Hence, the correct answer is option (D).

• Blood is made up of two parts i.e., fluid and blood cells. 
• The fluid part i.e., plasma contains water salts & protein and the blood cells comprise of RBCs, WBCs, and platelets. 
• The blood cells are suspended in plasma which constitutes 55% of body fluid.
• Hence, the correct answer is C.

Correct option: C

Explanation:

• Water carrying tubes transport water and minerals within a plant, from the roots, up to the stem and to all parts of the plant. 
• Vascular tissues are divided into three parts:
• Xylem: transports water
• Cambium: forms secondary vascular tissue
• Phloem: transports food
• 
  

Hence, ‘Xylem’ is the correct answer.