CBSE Class 7 Science Transportation in Animals and Plants Assignment

L-11 Transportation in Animals and Plants

Question 1. We have given one component of blood, write other three in the given spaces.
Answer: The four main components of blood are Plasma, Red Blood Cells (RBCs), White Blood Cells (WBCs), and Platelets. Based on the diagram provided, the three missing components are: Red Blood Cells, White Blood Cells, and Platelets.
In simple words: Blood is made of liquid plasma and three types of cells - red cells, white cells, and platelets.

Exam Tip: Remember that plasma forms the fluid matrix of blood in which cells are suspended.

Question 2. Match the following
Column I:
a) Its presence makes blood appear red.
b) Fight against germs that may enter our body.
c) Transport of food.
d) Transport of water.
e) Clotting of blood.

Column II:
i) Phloem
ii) Platelets
iii) Haemoglobin
iv) White blood cells
v) Xylem

Answer:
1. a - iii (Its presence makes blood appear red - Haemoglobin)
2. b - iv (Fight against germs that may enter our body - White blood cells)
3. c - i (Transport of food - Phloem)
4. d - v (Transport of water - Xylem)
5. e - ii (Clotting of blood - Platelets)
In simple words: Each component of the circulatory system in animals and plants has a specific function, such as carrying oxygen, fighting infections, or transporting water and nutrients.

Exam Tip: Memorize plant vascular tissues as 'Xylem for water (Xw)' and 'Phloem for food (Pf)' to avoid confusion.

Question 3. Record your own pulse rate per minute.
a) While resting -- ................. / min
b) After running for 4-5 minutes - ............... / min
Answer:
a) While resting - 72 / min (Typical normal resting pulse rate ranges between 72 to 80 beats per minute)
b) After running for 4-5 minutes - 120 / min (Pulse rate increases significantly during physical activity due to higher oxygen demand)
In simple words: Your heart beats faster when you exercise because your muscles need more oxygen.

Exam Tip: Pulse rate is measured as the number of heartbeats per minute and corresponds to your heart rate.

Question 4. Correct the following sentences by replacing the highlighted words.
a) Arteries are the vessels which carry carbon dioxide rich blood from all parts of the body back to the heart.
Answer: Arteries are the vessels which carry oxygen-rich blood from the heart to all parts of the body (or replace 'Arteries' with 'Veins').
In simple words: Arteries carry pure oxygenated blood away from the heart, while veins bring impure deoxygenated blood back to the heart.

Exam Tip: Pulmonary artery is the only exception as it carries carbon dioxide-rich blood from the heart to the lungs.

Question 4. b) Veins carry oxygen-rich blood from the heart to all parts of the body.
Answer: Veins carry carbon dioxide-rich blood from all parts of the body back to the heart (or replace 'Veins' with 'Arteries').
In simple words: Veins collect blood from body tissues and return it to the heart.

Exam Tip: Pulmonary vein is the only exception as it carries oxygen-rich blood from the lungs to the heart.

Question 4. c) Ammonia is the main excretory product of human being.
Answer: Ammonia is the main excretory product of fishes (or aquatic animals). (For human beings, it is urea).
In simple words: Humans excrete urea, whereas aquatic animals directly excrete highly soluble ammonia into water.

Exam Tip: The nature of excretory waste depends on the availability of water in the animal's habitat.

Question 4. d) Uric acid is the main excretory product of fishes.
Answer: Uric acid is the main excretory product of birds, insects, and lizards. (For fishes, it is ammonia).
In simple words: Birds and lizards excrete semi-solid uric acid to conserve water in their bodies.

Exam Ident: Uric acid excretion requires minimum water loss.

Question 4. e) Urea is the main excretory product of birds, lizards etc.
Answer: Urea is the main excretory product of human beings (and mammals). (For birds and lizards, it is uric acid).
In simple words: Mammals excrete urea dissolved in urine.

Exam Tip: Learn the three main nitrogenous wastes: Ammonia (fishes), Urea (humans/mammals), and Uric acid (birds/reptiles/insects).

Question 5. Label the following Diagram (A) - Sections of human heart.
Answer:
- Vena cava
- Right atrium
- Right ventricle
- Aorta
- Left atrium
- Left ventricle
In simple words: The human heart has four chambers: two upper atria and two lower ventricles, separated into left and right sides.

Exam Tip: The left side of the heart deals with oxygenated blood, while the right side deals with deoxygenated blood.

Question 5. Label the following diagram (B) - Human Excretory System.
Answer:
- Kidney
- Ureter
- Urinary bladder
- Urethra
In simple words: The human excretory system filters blood through kidneys to produce urine, which is stored in the bladder and released through the urethra.

Exam Tip: The functional units of the kidney responsible for filtering blood are called nephrons.

Question 6. Observe the given diagram and name the process. (C)
Answer: Transpiration
In simple words: Plants release excess water in the form of water vapour into the atmosphere through tiny pores called stomata on their leaves.

Exam Tip: Transpiration creates a suction pull that helps draw water and minerals upward from the roots to the leaves.