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?
The more basic characteristic for classifying organisms is the kind cells they are made of because there are a number of organisms which are living in a common habitat but they belong to different taxonomic groups. Organisms can be classified into eukaryotes (protista, fungi, plants and animals) and prokaryotes (monera) on the basis of cell type.
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.
Which organisms are called primitive and how are they different from the so-called advanced organisms?
How do gymnosperms and Angiosperms differ from each other?
Give three examples of the range of variations that you see in life-forms around you.
What are the major divisions in the Plantae? What is the basis for these divisions?
How do annelid animals differ from arthropods?
What are the differences between amphibians and reptiles?
Which division among plants has the simplest 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?
Certain force acting on a 20 kg mass changes its velocity from 5 m s-1 to 2 m s-1. Calculate the work done by the force.
What are the different means by which infectious diseases are spread?
The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?
Calculate the molecular masses of H2, O2, Cl2, CO2, CH4, C2H6, C2H4, NH3, CH3OH.
A stone is allowed to fall from the top of a tower 100 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25 m/s. Calculate when and where the two stones will meet.
What is the mass of—
(a) 1 mole of nitrogen atoms?
(b) 4 moles of aluminium atoms (Atomic mass of aluminium = 27)?
(c) 10 moles of sodium sulphite (Na2SO3)?
What precautions can you take in your school to reduce the incidence of infectious diseases?
State the universal law of gravitation.
A stone is thrown vertically upward with an initial velocity of 40 m/s. Taking g = 10 m/s2, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone?
What are canal rays?