Determining whether something is alive involves assessing various characteristics that are commonly associated with life. The criteria used to decide whether something is alive include:

Cellular Organization

Living beingsLiving beings are organisms that exhibit the key characteristics of life. These include the ability to grow, reproduce, maintain homeostasis, respond to stimuli, adapt through evolution, and undergo metabolism. They range from simple single-celled bacteria to complex multicellular organisms like humans, encompassing a vast diversity of life forms. are composed of cells, which are the basic units of life. These cells can be unicellular (consisting of a single cell) or multicellular (comprising many cells).


All living organisms exhibit metabolism, which includes all the chemical reactions that occur within the body. This involves processes like breaking down nutrients for energy (catabolism) and using energy to build up cellular components (anabolism). The Non-livingsNon-living things are entities that do not possess the characteristics of life. They do not grow, reproduce, respond to stimuli, or undergo metabolism. Examples include rocks, water, and man-made objects like buildings and machines. They can be natural or artificial and do not evolve through biological processes. does not do these activities.

Growth and Development

Living organisms grow and develop. In multicellular organisms, growth typically involves an increase in cell number and size. Development involves changes in the organism through its life cycle, such as a caterpillar developing into a butterfly.

Reproduction and Response to Stimuli

Reproduction: The ability to reproduce, either sexually or asexually, is a fundamental characteristic of living organisms. Reproduction is the process by which organisms give rise to new individuals of the same species.

Response to Stimuli: Living organisms can respond to environmental stimuli. This can range from simple responses like bacteria moving towards nutrients, to complex responses like animals perceiving and reacting to their surroundings.

Homeostasis and Adaptation

Homeostasis: The ability to maintain a stable internal environment (homeostasis) is a key feature of living organisms. This includes regulating factors like temperature, pH, and water content, irrespective of external environmental conditions.

Adaptation: Living organisms exhibit adaptations to their environment. These are traits or behaviors that increase their chances of survival and reproduction. Adaptations result from evolutionary processes over generations.

Energy Utilization: All living organisms require and utilize energy. In most cases, this energy is derived from food. Autotrophs, like plants, capture energy from sunlight through photosynthesis, while heterotrophs obtain energy by consuming other organisms.

These criteria collectively help in determining whether an entity is alive. However, it’s important to note that some cases may not be straightforward. For example, viruses exhibit some characteristics of life, such as reproduction and genetic material, but they lack others, like metabolism and cellular structure, leading to debate about their classification as living or non-living.

Discuss this question in detail or visit to Class 10 Science Chapter 5 for all questions.
List of Questions of Class 10 Science Chapter 5

Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
What criteria do we use to decide whether something is alive?
What are outside raw materials used for by an organism?
What processes would you consider essential for maintaining life?
What are the differences between autotrophic nutrition and heterotrophic nutrition?
Where do plants get each of the raw materials required for photosynthesis?
What is the role of the acid in our stomach?
What is the function of digestive enzymes?
How is the small intestine designed to absorb digested food?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
How is oxygen and carbon dioxide transported in human beings?
How are the lungs designed in human beings to maximise the area for exchange of gases?
What are the components of the transport system in human beings?
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
What are the components of the transport system in highly organised plants?
How are water and minerals transported in plants?
How is food transported in plants?
Describe the structure and functioning of nephrons.
What are the methods used by plants to get rid of excretory products?
How is the amount of urine produced regulated?
How are fats digested in our bodies? Where does this process take place?
What is the role of saliva in the digestion of food?
What are the necessary conditions for autotrophic nutrition and what are its byproducts?
What are the differences between aerobic and anaerobic respiration?
How are the alveoli designed to maximise the exchange of gases?
What would be the consequences of a deficiency of haemoglobin in our bodies?
Describe double circulation of blood in human beings. Why is it necessary?
What are the differences between the transport of materials in xylem and phloem?
Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Last Edited: November 16, 2023