Unicellular organisms are immortal, whereas multicellular organisms are not.  Justify.

2

(a)

Reptiles and frogs are oviparous animals; yet they differ in certain aspects of reproduction.  Bring out the differences and mention which of the two animals has more advantage in survival.

2

(a)

Why is it that there is no natural death in single-celled organisms like Amoeba and bacteria?

2

(a)

In oogamy, female gamete is large and non-motile but the male gamete is reverse in its properties. Why such type of adjustment is there in higher organisms?

2

(a)

How do gemmules and gemma cup differ from each other?

2

(a)

Fill in the blanks with their correct vegetative propagules:
a) Agave __________
b) Hydra__________
c) Onion__________
d) Mint__________

2

(a)

In a pond ecosystem you may find the plant with purple flowers that spread very fast to cover the entire pond within a short span of time. How does it spread? How does it harm the aquatic body?

2

(a)

Why do we say there is no natural death in single-celled organisms?

2

(a)

You have learnt about vegetative reproduction in plants. What do you think, is vegetative reproduction also a type of asexual reproduction? Why do you say so? Is the term clone applicable to the individuals formed by vegetative reproduction?

2

(a)

Algae and fungi shiftto sexual method ofreproduction just before the onset of adverse conditions. Find out how sexual reproduction enables these organisms to survive during unfavourable conditions. Why is sexual reproduction favoured under such conditions?

2

(a)