Theory:

Have you ever seen the world around us? It is filled with various things which can be broadly classified as living (biotic) and non-living (abiotic).
 
shutterstock_1964275852.jpg
Biotic and abiotic factors
 
Do you know the basis of classification? Recall your lower grades as we have already dealt with these.
The organisms that perform various processes for their survival are known as living organisms.
The prevalence of life on the planet earth is mainly based on certain processes that maintain the proper functioning of the body organ systems. For example, living organisms perform various metabolic activities such as respiration, digestion, growth, excretion, etc.
 
An organism is considered to be living based on its characteristics, as shown in the image below.
 
Mind maps - Divya (s2).png
Characteristics of living organisms
 
Hence, an organism is said to be alive if it performs these processes and characteristics. Animals are organisms whose movements can be seen with the naked eye.
Example:
Running, chewing, breathing all these movements can be seen.
Hence they can easily be classified as dead and alive. But what about plants? How can we say that they are alive or dead? In such cases, their measurable development indicates that they are alive.
 
In general, we say whether a plant is alive or dead based on its leaf colour. A plant whose leaves are green in colour is considered as biotic. This is because of the chlorophyll present in the leaves of these plants aid in photosynthesis. But this cannot always be agreed as there plants which have leaves other than green colour.
 
800px-SZ_深圳_Shenzhen_蛇口_Shekou_花園城市中心_Garden_City_Center_red_n_green_leaves_plant_彩葉草_Coleus_Scutellarioides_October_2017_IX1_01.jpg
Plant with green and non-green leaves
 
Even in terms of movement and growth, not always can these processes observed both in plants and animals. But still, the organism is considered to be alive. Thus, a human is said to live while sleeping even though no movement is observed.
 
people-2537324_1920.jpg
Woman sleeping
 
Microorganisms are invisible to the naked eye. But are still considered to be living due to these processes which are observed in them.
As discussed above, certain processes play a prominent role in maintaining life. This topic will help us in understanding these maintenance processes in plants and animals in detail.
Reference:
https://socratic.org/questions/justify-virus-as-a-living-or-non-living-organism
https://commons.wikimedia.org/wiki/File:SZ_%E6%B7%B1%E5%9C%B3_Shenzhen_%E8%9B%87%E5%8F%A3_Shekou_%E8%8A%B1%E5%9C%92%E5%9F%8E%E5%B8%82%E4%B8%AD%E5%BF%83_Garden_City_Center_red_n_green_leaves_plant_%E5%BD%A9%E8%91%89%E8%8D%89_Coleus_Scutellarioides_October_2017_IX1_01.jpg
https://pixabay.com/photos/people-woman-sleep-2537324/