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.
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?
What are polyatomic ions? Give examples.
How are fish obtained?
What is genetic manipulation? How is it useful in agricultural practices?
An object of mass 100 kg is accelerated uniformly from a velocity of 5 m s-1 to 8 m s-1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.
Which method is commonly used for improving cattle breeds and why?
What is a tissue?
How are living organisms dependent on the soil? Are organisms that live in water totally independent of soil as a resource?
Two children are at opposite ends of an aluminium rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the sound wave in air and in aluminium to reach the second child.
Write the chemical formulae of the following.
(a) Magnesium chloride
(b) Calcium oxide
(c) Copper nitrate
(d) Aluminium chloride
(e) Calcium carbonate.
If number of electrons in an atom is 8 and number of protons is also 8, then (i) what is the atomic number of the atom? and (ii) what is the charge on the atom?