Which one of the following statements related to capillaries is correct?

Which human-made material cannot be broken down by the action of bacteria?

A section of DNA providing information for one protein is called

What are the functions performed by the testis in human males

Depletion of ozone is mainly due to

In which part of the alimentary canal food is finally digested?

Which of the following statements are true?
(i) Sudden action in response to something in the environment is called reflex action
(ii) Sensory neurons carry signals from spinal cord to muscles
(iii) Motor neurons carry signals from receptors to spinal cord
(iv) Impulse from a receptor to a muscle or a gland is called reflex arc

Mention the significance of food web.

What is the main difference between sperms and eggs of humans? Write the importance of this difference.

Mala is four-month pregnant and is worried whether the child is male or female. One day she reads an advertisement regarding a medicine which of taken for 3 months results in birth of male child. What should she do?
(a) Get the medicine and take it regularly.
(b) Visit a doctor and discuss the problem with him/her.
(c) What, in your opinion, are the chances of having a male child?

What are gustatory receptors?

Given below is a diagram of bisexual flower.

(i) Draw the missing parts of a flower.
(ii) Explain with help of a diagram, how the male germ cells reaches the female germ cells present in the ovary?
(iii) Justify the statement "Pollination may occur without fertilisation, but fertilisation will not take place without pollination."

Draw a diagram of a human female reproductive system and label the part
(i) that produces egg
(ii) where fusion of egg and sperm take place
(iii) where zygote is implanted
What happens to human egg when it is not fertilised?

(i) State the role played by the following in the process of digestion.
(a) Enzyme trypsin
(b) Enzyme lipase
(ii) List two functions of finger-like projections present in the small intestine.

What evidence do we have for the origin of life from inanimate matter?

Assertion: A food chain comprises of producers and consumers.
Reason: Consumers can be herbivores, carnivores and omnivores.
Codes
(a) Both A and R are true and R is correct explanation of the assertion.
(b) Both A and R are true but R is not the correct explanation of the assertion.
(c) A is true but R is false.
(d) A is false but R is true

Assertion: Darwin's theory of evolution tells us how life evolved from simple to more complex forms.
Reason: Mendel's experiments give us the mechanism for the inheritance of traits from one generation to the next.
Codes
(a) If both assertion and reason are true and the reason is correct explanation of assertion.
(b) If both assertion and reason are true but reason is not a correct explanation of assertion.
(c) If assertion is true and reason is false.
(d) If both assertion and reason are false.

Given are the sections of two pipes, A and B. If you need to represent blood vessels with these, which of the pipes would correspond to the artery and which one to a vein. Identify it and answer the following questions.

(i) B is best defined as the vessel which
(a) always supply oxygenated blood to the different organs
(b) always carry blood away from the heart to different organs
(c) always break up into capillaries that reunite to form a vein
(d) always carry blood from one visceral organ to another visceral organ.
(ii) In A, valves are present to check backward flow of blood flowing at

(iii) Which of the following statements is correct regarding A?
(a) Carries blood from an organ towards the heart
(b) Always carry oxygenated blood with single exception
(c) Carries blood from heart towards the organ
(d) All of these
(iv) Which of the following statements is incorrect?
(a) A has typically larger lumen than B.
(b) Walls of B are elastic enabling them to stretch and shrink during changes in blood pressure
(c) Flow of blood is slower in A than in B
(d) None of these
(v) Blood pressure in the pulmonary artery is