Archives

Aquatic animals like fish excrete their wastes in gaseous form as (a) Oxygen (b) Hydrogen (c) Ammonia (d) Nitrogen

c) Ammonia Aquatic animals perform the procedure of 'Excretion' depending on the availability and unavailability of water. They excrete their... View Article

In a tall tree, which force is responsible for pulling water and minerals from the soil? (a) Gravitational force (b) Transportation force (c) Suction force (d) Conduction force

c) Suction force Roots absorb minerals and water from the soil constantly. The suction force is created by evaporation of water from the... View Article

In which of the following parts of the human body are sweat glands absent? (a) Scalp (b) Armpits (c) Lips (d) Palms

c) Lips Sweat glands are present in scalp, armpits, and palms but not in lips. So, lips do not secrete sweat. Sweat glands are absent in the... View Article

The absorption of nutrients and exchange of respiratory gases between blood and tissues takes place in – (a) veins (b) arteries (c) heart (d) capillaries

d) Capillaries Exchange of gases, nutrients, and waste between blood and tissue occurs in the capillaries. Capillaries are tiny vessels that... View Article

They are pipe-like, consisting of a group of specialized cells. They transport substances and form two-way traffic in plants. Which of the following terms qualify for the features mentioned above? (a) Xylem tissue (b) Vascular tissue (c) Root hairs (d) Phloem tissue

d) Phloem tissue Phloem is also important as the xylem tissues for the vascular system of plants. The main activity of this tissue is to... View Article

The muscular tube through which stored urine is passed out of the body is called – (a) kidney (b) ureter (c) urethra (d) urinary bladder

C) Urethra A hollow tube is located between 'Urinary Meatus' and 'Urinary Bladder' is termed as Urethra. A tube in the kidney through which... View Article

A food stall owner was preparing dough for making bhaturas. He added a pinch of yeast and sugar to the dough and left it in a warm place. After few hours, the dough had risen. There was a sour smell too. (a) Why did the dough rise? (b) Why did the dough smell sour? (c) Why was sugar added to the dough? (d) What would have happened if the dough was kept in the refrigerator, soon after it was prepared?

a) Yeast are the single cell organisms which perform anaerobic respiration. The dough rose because of the release of carbon dioxide which is a... View Article

Observe Figure carefully and answer the following questions. (a) Which process is being tested in the activity? (b) What is the result of the activity? Give reasons.

a) As the air is being released from the nose, the process of exhalation is being tested here. b) In the first case i.e. test tube A only water... View Article

Observe Figure carefully and answer the following questions. (a) In which jar, will the amount of CO2 be the highest and why? (b) In which jar, will the amount of CO2 be the lowest and why?

In jar A only plant is present and plants take up the carbon dioxide present the atmospheric air. In jar B along with the plant, mice are also... View Article

Paheli participated in a 400 m race competition held at her school and won the race. When she came home she had mixed feelings of joy and pain as she had cramps in her leg muscles. After a massage, she was relieved of the pain. Answer the following questions related to the situation. (a) What can be the possible reasons for the pain in her legs? (b) Why did she feel comfortable after a massage?

a) During heavy exercise like running a deficiency of oxygen is created in the muscle cells. This deficiency leads to anaerobic respiration in... View Article

Insects and leaves of a plant have pores through which they exchange gases with the atmosphere. Can you write two points of differences between these pores with respect to their position, number and extension into the body?

Spiracles are the tiny pores present in the insects like cockroaches which help in gaseous exchange whereas stomata are the openings present on... View Article

Whenever we feel drowsy or sleepy, we start yawning. Does yawning help us in any way?

When we feel drowsy, rate of breathing is decelerated, that means enough oxygen is not supplied to lungs, it makes us yawn. And when we yawn, we... View Article

On a very cold morning, Boojho and Paheli were talking with each other as they walked down to their school. They observed that the air coming out of their mouth looked like smoke. They were amused and wondered how it happened. Help them find the answer.

On a cold day, the warm and moist air exhaled by us condenses into mist when it comes in contact with the cold air of the atmosphere. This looks... View Article

On average, an adult human being at rest breathes 15–18 times per minute. The breathing rate, however, may differ under different conditions. Arrange the following activities given in the box in order of increasing breathing rates and give a reason for your answer. (sleeping, cycling, brisk walk, watching T.V.)

Sleeping > Watching > T.V. > Brisk Walk > Cycling The breathing rate becomes faster when we are working. The more is strenuous work,... View Article

Which gas present in the air is essential for aerobic respiration? What is the role of oxygen during respiration?

Aerobic respiration occurs in the presence of oxygen gas or O2. Oxygen oxidizes the food and breaks it into smaller molecules so that energy... View Article

Pick the odd-one-out from each of the groups given below on the basis of respiratory organs. Give a reason for your answer. (a) cockroach, grasshopper, snail, ant (b) lizard, cow, earthworm, snake (c) crocodile, whale, dolphin, fish (d) snake, tadpole, crow, goat

Answer: The respiratory system is an organ system responsible for exchanging gases in animals. It is the system that uses oxygen and expels... View Article

Fill in the blanks with suitable words. (a) The roots of a plant take up oxygen from the trapped between the particles. (b) Diaphragm forms the _ of the chest cavity. (c) Exchange of gases in the leaves takes place with the help of . (d) Cockroaches breathe with the help of air tubes called _____.

a) The roots of a plant take up oxygen from the air trapped between the soil particles. The roots use up the oxygen available to them from the... View Article

M	T	W	T	F	S	S
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23	24	25	26	27	28	29
30	31