Biology SSS 1 First Term



Performance Objectives

Student should be able to:

  1. Explain irritability as the basic characteristics of protoplasm
  2. Gives the type of responses


All living things are capable of responding to internal and external stimuli. The ability to do this is called irritability or sensitivity. By this means, plants and animals are able to detect and respond to changes in their environment. Irritability is one of the basic characteristics of a living organism.


Types of Responses

Generally, animals respond very quickly to external stimuli while plants respond slowly. Again, only certain organs respond to external stimuli in plants but in animals, often, the whole organism responds to the stimulus. There are three.... View More

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