What are the major divisions in the Plantae? What is the basis for these divisions?
The kingdom Plantae is divided into five main divisions: Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms.
The classification depends on the following criteria:
• Differentiated / Undifferentiated plant body
• Presence / absence of vascular tissues
• With/without seeds
• Naked seeds/ seeds inside fruits
(i) Thallophyta : these are simple , thalloid and undifferentiated body parts. They do not have roots, stems and leaves.
(ii) Bryophyta : their plant body is more differentiated and has root ,stem and leaf-like body parts. They do not have vascular tissue.
(iii) Pteridophyta : they have true root, stem and leaf. They possess well differentiated vascular tissue.
(iv) Gymnosperm : the plants in which ovules are not enclosed by any ovary wall i.e naked - seeded plants.
(v) Angiosperm : seeds are enclosed in fruits.
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.
How do annelid animals differ from arthropods?
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?
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?
Convert into mole.
(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide.
What causes winds?
In which of the three media, air, water or iron, does sound travel the fastest at a particular temperature?
Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?
Write the formula to find the magnitude of the gravitational force between the earth and an object on the surface of the earth.
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?
Classify the following into elements, compounds and mixtures.
(a) Sodium
(b) Soil
(c) Sugar solution
(d) Silver
(e) Calcium carbonate
(f) Tin
(g) Silicon
(h) Coal
(i) Air
(j) Soap
(k) Methane
(l) Carbon dioxide
(m) Blood
What do we get from cereals, pulses, fruits and vegetables?
Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?
What are the different states in which water is found during the water cycle?