Which organisms are called primitive and how are they different from the so-called advanced organisms?
Primitive organisms are those which have a simple body structure (lower organisms) and ancient body design that have not changed much. The organisms that have acquired more complex structure and body design are known as advanced organisms or higher organisms. For example, an Amoeba is more primitive as compared to a starfish. Amoeba has a simple body structure and primitive features as compared to a starfish. Hence, an Amoeba is considered more primitive than a starfish.
How do poriferan animals differ from coelenterate animals?
Explain the basis for grouping organisms into five kingdoms.
Explain how animals in Vertebrata are classified into further subgroups.
How do gymnosperms and Angiosperms differ from each other?
What are the major divisions in the Plantae? What is the basis for these divisions?
Give three examples of the range of variations that you see in life-forms around you.
Which do you think is a more basic characteristic for classifying organisms?
(a) the place where they live.
(b) the kind of cells they are made of. Why?
How do annelid animals differ from arthropods?
What are the differences between amphibians and reptiles?
In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?
Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?
State the universal law of gravitation.
Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
What is meant by a pure substance?
How does the sound produced by a vibrating object in a medium reach your ear?
In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium observations are in agreement with the law of conservation of mass.
sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water
What are canal rays?
State any two conditions essential for good health.
How is our atmosphere different from the atmospheres on Venus and Mars?
A stone is thrown in a vertically upward direction with a velocity of 5 m s-1. If the acceleration of the stone during its motion is 10 m s-2 in the downward direction, what will be the height attained by the stone and how much time will it take to reach there?
A racing car has a uniform acceleration of 4 m s-2. What distance will it cover in 10 s after start?
A trolley, while going down an inclined plane, has an acceleration of 2 cm s-2. What will be its velocity 3 s after the start?
What does the odometer of an automobile measure?
Why are we normally advised to take bland and nourishing food when we are sick?
Define 1 watt of power.
In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?
• if you get jaundice,
• if you get lice,
• if you get acne.
Why?
Name two biologically important compounds that contain both oxygen and nitrogen.
Convert the following temperatures to the Celsius scale.
(a) 300 K (b) 573 K.
What are polyatomic ions? Give examples.