Air is blown in between two pith balls suspended freely.
a)What will happen to the balls?
(i)They repel each other.
(ii)They attract each other.
(iii)They start oscillating.
(iv)They remain in their initial position.
(v)They fall on the ground.
b)Give your explanation.

State the principle as to why these balls attract each other when air is blown between them.

Read the following statements carefully and select the appropriate option given below. (i) The distal end of the filament is attached to the thalamus or the petal of the flower. (ii) The pollen grains represent the male sporophyte. (iii) The microsporangia develop further and become embryo sac. (iv) In over 60 per cent of naked seeded plant, pollen grains are shed at this 2-celled stage. (v) As anthers mature and dehydrate the microspores, dissociate from each other and develop into pollen grains.

An urn contains 9 red, 7 white and 4 black balls. If two balls are drawn at random, find the probability. that, (i) both the balls are red (ii) one ball is white, (iii) the balls are of the saime colour (iv) one is white and other red.

A projectile is an object projected into air with a velocity V so that it is moving under the influence of gravity. a)What is the shape of the path of projectile? b)As a projectile moves in its path,is there any point along the path where the velocity and acceleration vectors are perpendicular to each other. c)If E is energy with a projectile is projected, (i)What is the kinetic energy at the highest point. (ii)What is P.E at highest point?

Which of the following statement regarding species interdependence are ture? I . An association of two species where one is benefitted and other remain unaffected is called mutualism. II. An interspecific association where both patnrs derive benefit from each other is called commensalism. III. A dircet food realition between two species of animals in which one animals kills and feed on another,is referred as predation. Iv.A realtionship between two of organisms where both the patners are benifitted from each other is called symbiosis.