Explanation

Inspiration, or inhalation, involves the contraction of two main muscle groups:

Diaphragm: a dome-shaped muscle that separates the chest cavity from the abdominal cavity.

When it contracts, it flattens and increases the volume of the chest cavity.

Intercostal muscles: muscles located between the ribs.

When they contract, they pull the ribs outward and upward, increasing the volume of the chest cavity.

Explanation

A respiratory surface, such as the alveoli in lungs or the surface of gills, possesses the following properties:

• Thin: allows for efficient gas exchange
• Wet: facilitates the exchange of gases between the surface and the surrounding environment
• Permeable: allows gases to pass through the surface
• Very large: provides a large surface area for gas exchange to occur

Explanation

Each stoma (singular of stomata) is formed by two guard cells, which are specialized cells that surround the stoma and control its opening and closing.

The guard cells swell or shrink to adjust the aperture of the stoma, regulating gas exchange and transpiration in plants.

Explanation

Plants exchange gases through:

• Roots: absorb oxygen and release carbon dioxide through small openings called root hairs
• Stomata (singular: stoma): tiny openings on leaf surfaces that allow for gas exchange (CO2 in, O2 out)
• Stem: some plants have aerial roots or stem cuticles that allow for gas exchange

Explanation

Gaseous exchange refers to the exchange of gases between an organism and its environment.

Both photosynthesis and respiration involve gaseous exchange:

• Photosynthesis: takes in carbon dioxide (CO2) and releases oxygen (O2)
• Respiration: takes in oxygen (O2) and releases carbon dioxide (CO2)

Explanation

• A population is a localized group of organisms that belong to the same species and live in a specific geographic area.
• It is a unit of evolution, and its members share a common gene pool.