I believe the correct answer is the second option, or b.
Diffusion is the spontaneous movement of gases, without the use of any energy or effort by the body, between the gas in the alveoli and the blood in the capillaries in the lungs. Perfusion is the process by which the cardiovascular system pumps blood throughout the lungs.
Hydra and Obelia are cnidarians (species of aquatic organisms) that belongs to the Class Hydrozoa.
Several ways in which Obelia differs from Hydra are;
- Hydra is a predative species that lives on substrates such as wood, while Obelia is a colonial species that lives as polyps on branched frameworks.
- Hydra is found in freshwater habitats, while Obelia is found in marine habitats.
- Hydra undergoes the medusa form in its life cycle, while Obelia undergoes the two forms (polyp and medusa) in its life cycle.
- Hydra has great regenerative powers while Obelia does not have great regenerative powers.
A heterogeneous mixture is a mixture in which the components of that mixture can be seen and taken apart easily.
Example:- Chex mix is a brand of chips/snacks that its components can be easily seen apart.
