Skip to main content

Class 7 ch_ 1 science solution

 Q.1. Why do organisms need to take food?

Ans. Food is needed by all organisms for many purposes:

(a) The main function of food is to help in growth.

(b) Food provides energy for movements such as running, walking or raising our arm.

(c) Food is also needed for replacement and repairing damaged parts of body.

(d) Food gives us resistance to fight against diseases and protects us from infections

 

Q.3. How would you test the presence of starch in leaves?

Ans. The presence of starch in leaves can be tested by Iodine test. When we remove chlorophyll from leaf by boiling it in alcohol and then put 2 drops of iodine solution, its colour change to blue indicates the presence of starch.

Q.4. Give a brief description of the process of synthesis of food in green plants.

Ans. The green plants have chlorophyll in the leaves. The leaves use C02 and water to make food in presence of sunlight.

 

Q.5. Show with the help of a sketch that the plants are the ultimate source of food.

 

Q.6. Fill in the blanks:

(a) Green plants are called ________________ since they synthesise their own food.

(b) The food synthesised by the plants is stored as ________________ .

(c) In photosynthesis solar energy is captured by the pigment called ________________

(d) During photosynthesis plants take in ________________ and release ________________ .

Ans. (a) autotrophs (b) starch (c) chlorophyll (d) carbon dioxide, oxygen

Q.7. Name the following:

(i) A parasitic plant with yellow, slender and tubular stem.

(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.

(iii) The pores through which leaves exchange gases.

Ans. (i) cuscuta (ii) Insectivorous plant (iii) Stomata

Q.8. Tick the correct answer:

(a) Amarbel is an example of:

(i) Autotroph (ii) Parasite (iii) Saprotroph (iv) Host

(b) The plant which traps and feeds on insects is:

(a) Cuscuta (ii) China rose {iii) Pitcher plant (iu) Rose

Ans. (a) (ii) Parasite (b) (iii) Pitcher plant

Q.9. Match the items given in Column I with those in Column II:

 

Q.10. Mark T’ if the statement is true and ‘F’ if it is false:

(i) Carbon dioxide is released during photosynthesis. (T/F)

(ii) Plants which synthesise their food themselves are called saprotrophs. (T/F)

(iii) The product of photosynthesis is not a protein. (T/F)

(iv) Solar energy is converted into chemical energy during photosynthesis. (T/F)

Ans. (a) F (ii) F (iii) T (iu) T

Q.11.Choose the correct option from the following.

Which part of the plant takes in carbon dioxide from the air for photosynthesis?

(i) Root hair (ii) Stomata (iii) Leaf veins (iv) Sepals

Ans. (ii) Stomata

Q.12. Choose the correct option from the following:

Plants take carbon dioxide from the atmosphere mainly through their:

(i) Roots (ii) Stem (iii) Flowers (iv) Leaves

Ans. (iv) Leaves


Comments

Popular posts from this blog

No. Of imageimages

Multiple Images with Plane Mirrors Introduction The number of images formed by two adjacent plane mirrors depends on the angle between the mirror. If  θ  (in degrees) is angle between the plane mirrors then number of images are given by, n=n = 360 θ − 1. We verify this formula in this experiment. Apparatus Two plane mirrors, protractor to measure angle, candle, matchbox. Procedure Take two plane mirrors (without frame). Place both the mirrors side by side and fix the junction where they meet with a cello tape. Now you will be able to open and close the mirrors like a book. Place both the mirrors at a small angle apart in the upright position on the floor. Place a lighted candle in the space between the two mirrors. You will observe many images of the candle which makes a beautiful scene. Now, by gradually decreasing the angle between the mirrors observe the images being formed. You will now observe more and more numbers of images of the candle. Similarly, if the angle between ...

General question

 43. Who was awarded the Lokmanya Tilak National Journalism Award in the year 2020? Sanjay Gupta (editor-in-chief of Jagran) 44. Who was awarded with Muppavarapu Venkaiah Naidu National Award for Excellence? Dr M S Swaminathan 45. Which district was awarded the Plastic Waste Management Award 2020? Dibrugarh district during Swachhta Hi Sewa 2019 46. Which district is awarded the Swachhata Darpan Award 2020? Peddapalli district 47. Who was awarded the Prem Bhatia Award for political reporting for his work on issues related to the COVID19 pandemic? Dipankar Ghose 48. Who received the Richard Dawkins award 2020? Javed Akhtar 49. Who was awarded with Karmaveer Chakra Award instituted by the United Nations and International Confederation of NGO? Sunil Yadav 50. Name the famous award received by Kala Narayanasamy. President’s Award in Singapore for outstanding services https://youtu.be/o3R7AfIGK9A Plese support us

Class 8 Chapter 11 Time and Work

 Access answers to Maths RD Sharma Solutions For Class 8 Chapter 11 Time and Work 1. Rakesh can do a piece of work in 20 days. How much work can he do in 4 days? Solution: The given details are, Time taken by Rakesh to do a piece of work is 20 days Work done by Rakesh in 1 day = 1/20 Work done by Rakesh in 4 days = 4 × 1/20 = 1/5 ∴ 1/5th work can be done by Rakesh in 4days. 2. Rohan can paint 1/3 of a painting in 6 days. How many days will he take to complete painting? Solution: The given details are, Number of days taken by Rohan for painting 1/3 of painting is 6 days Number of days taken by Rohan to complete the painting = 6/(1/3) = 6 × 3 = 18 ∴ Rohan can complete painting in 18days. 3. Anil can do a piece of work in 5 days and Ankur in 4 days. How long will they take do the same work, if they work together? Solution: The given details are, Anil can do a piece of work in 5 days Work done by Anil in 1 day = 1/5 Ankur can do same work in 4 days Work done by Ankur in 1 day = 1/4 Wor...