A tough, dormant form of bacteria that is highly resistant to environmental stress, enabling the bacterium to survive harsh conditions.

The formation of bone tissue within a cartilage model during the development of the skeletal system.

A glandular structure found in the pharynx of certain chordates, involved in mucus secretion to trap food particles.

The hypothesis that certain organelles, like mitochondria and chloroplasts, originated from free-living bacteria that formed symbiotic relationships with early eukaryotic cells.

A symbiotic relationship in which one organism lives inside the cells or body of another, often resulting in mutual benefits.

Referring to a mutualistic relationship in which one organism lives inside the cells of another, often seen in symbiotic relationships between microorganisms and their hosts.

The tissues that arise during the development of an embryo, from which all organs and body parts will form.

The movement of individuals or populations from one region to another, typically for reasons like better living conditions or environmental changes.

A chronic lung disease characterized by the destruction of alveolar walls, leading to reduced lung function and difficulty breathing.

Data and observations that are derived from sensory experience or experimentation rather than theory.