CBSE Class 10 Answered

Spore is a small, usually single-celled reproductive body that is highly resistant to desiccation and heat and is capable of growing into a new organism. It is adapted for dispersion and surviving for extended periods of time in unfavorable conditions. It is produced especially by certain bacteria, fungi, algae, and nonflowering plants. If environmental conditions are suitable, the spore will develop into a new individual. 

Advantages of reproduction through spores to the organism:

i) Spores come in a wide variety of forms and are produced and dispersed in many different ways.

ii) Spores are very effective, because they are small and light, and so can be carried by wind, water or animals; so they can travel far away from the parent, perhaps to better conditions.

iii) Some spores have thick walls which can give them protection against unfavorable conditions.

iv) Because the spores are so small, the organism can afford to release more of them, so there will be more spores surviving. It doesn't take much in the way of energy to produce a spore as opposed to making seeds and fruit.

v) Spores do not need fertilizing and will grow whenever the correct conditions are met.