What does it mean to absorb in biological terms?

In biological terms, absorption refers to the process by which living organisms take up substances, such as nutrients, water, and other essential compounds, into their tissues. This process is fundamental for growth, maintenance, and overall health, as it allows plants and animals to utilize resources from their environment. For example, in plants, the roots absorb water and minerals from the soil, which are then transported throughout the plant to support cellular functions. In animals, the digestive system absorbs nutrients from food, enabling energy production and growth.

The other options do not align with the biological definition of absorption. Releasing substances into the atmosphere involves processes like transpiration or exhalation, which is distinct from uptake. Emitting energy in response to stimuli pertains to response mechanisms in organisms and does not involve the uptake of substances. Breaking down materials into simpler forms is a description of digestion or decomposition, rather than absorption, which specifically focuses on the uptake of materials into an organism's tissues.