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NaiveAbafar3712

Hello! I have a hard time understanding the characteristics that define living things. Can you help me?

Emilie L

Thank you for your question!

• Every living being forms a complex whole whose basic subunit is the cell. Living things are made of a single cell (unicellular) or more than one cell (multicellular). Cells are containers or chambers that are partially isolated from their environment. They are the basic unit of living organisms. For example, the human body is an assembly of multiple cells that work together. Conversely, viruses are not cells and are therefore considered non-living by most scientists.
• Every living being reacts to stimuli: a stimulus (stimuli in the plural) such as light, color, sound, smell, etc causes organisms to react. For example, the body reacts to intense heat (stimuli) by producing the sensation of pain (reaction).
• All living things interact with their environment: although living organisms are made up of cells that are partially isolated from their environment, they use their resources to eat, breathe, and reject their waste. For example, plant cells exchange gas with the air around them in order to extract the carbon dioxide necessary for photosynthesis.
• All living things grow and develop: living things must be able to grow and repair themselves in order to survive. For example, children grow, and wounds heal.
• All living things use energy since energy fuels chemical reactions within cells. For example, mitochondria generate energy thanks to a combustion reaction.
• All living things reproduce: living things must reproduce themselves in order for their species to keep existing after the death of an individual. For example, pollinated flowers produce seeds from which new plants will sprout.
• Every living being adapts to changes in its environment: through evolution, species constantly adapt to changes in their environment. For example, primitive giraffe ancestors did not have long necks. However, natural selection favored longer-necked giraffes leading to an increase in giraffe neck length over time.

I hope you found my answer helpful :).

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