Answer: Option A. -> True : A Theaortais the largest artery in our body. It conveys oxygenated blood from the heart to the smaller arteries which takes it to all other parts of the body.
Question 22. Which of the following organism excretes ammonia?
Answer: Option D. -> Fishes : D All the nitrogenous wastes in the fishes are converted into ammonia before it is excreted out into the water. This ammonia directly dissloves in the water. Birds and lizards excrete nitrogenous wastes as uric acid. The excretory product in humans is urea.
Question 23. The _____ join up to form veins which empty carbon dioxide rich blood into the heart
Answer: Option D. -> capillaries : D Arteries transport oxygenated blood to all parts of the body form the heart. On reaching the tissues, arteries divide into capillaries. After delivering oxygen, now the capillaries join to form veins. The veins carry the carbon dioxide rich blood to the heart.
Question 24. In which body cavity is the heart located?
Answer: Option C. -> Chest cavity : C The heart is located in the chest cavity, also called thoracic cavity. It is protected by the rib cage. Chest cavity also houses the lungs.
Question 25.Transpiration is important for plants because: I: It removes extra water II: It cools down the plant III: It helps in transport of food IV: It helps in transport of water upwards
Answer: Option C. -> I, II and IV : C Transpirationis defined as the process where plants expel excess water aswater vapor through pores in their leaves called stomata.This process removes excess water,creates a suction pull to help in the transport of water upwardsand coolsdown the plant. The phloem tissues help in the transport of food.
Question 26. Which of the following is a component of plasma?
Answer: Option D. -> Water : D Plasma is the fluid component of the blood. It is derived when all the blood cells - red blood cells, white blood cells and platelets are separated from whole blood. The remaining straw-coloured fluid is 90–92 percent water and dissolved nutrients, proteins, waste products and hormones.
Question 27.Name the three types of blood vessels. Also, write their functions. [3 MARKS]
: Each point: 1 Mark Blood vessels carry blood to different parts of the body. There are three major types of blood vessels. a. The arteries, which carry blood away from the heart b. The capillaries, which enable the actual exchange of oxygenand nutrientsbetween the blood and the cells c. The veins, which carry blood from the capillaries back towards the heart.
Question 28. Answer the follwoing questions: [5 MARKS] 1.Where is urine formed? 2. Where is urine stored? 3. Which part of the excretory system is responsible for the transport of urine from the kidneys to the bladder? 4. What is the normal composition of urine? 5. What is the major excretory product in humans?
: Each answer: 1 Mark 1. Urine is formed in the kidneys. 2. Urine is stored in the urinary bladder. 3. The ureters transport the urine formed in the kidneys to the bladder. 4. The normal composition of urine is consists of 95% of water, 2.5 % of urea and 2.5% of other waste products. 5. The major excretory product in humans is urea.
Question 29.Which part of the plant prepares food? Name and explain the process. [3 MARKS]
: Location: 1 Mark Process: 2 Marks Plants absorb water and mineral nutrients from the soil through the roots and transport it to the leaves. The leaves prepare food for the plants, using water and carbon dioxide in the presence of sunlight and chlorophyll. This process is called photosynthesis. The prepared food is in the form of glucose.
Question 30. Answer the following: [3 MARKS] 1.Which is the major excretory product of fishes? 2. Which is the major excretory product of birds? 3. Which is the major excretory product of humans?
: Each answer: 1 Mark 1. The major excretory product of fishes is ammonia. 2. The major excretory product of birds is uric acid. 3. The major excretory product of humans is urea.
