I think its soluble fiber will be the answer
Their shapes fit snugly together
Living indicators are species that are sensitive to changes in the environment. For example air pollution can be monitored by looking at lichen, which are sensitive to sulphur dioxide in the air. The number of lichen at a particular location indicates how clear the air is. Similarly, mayfly larvae are good indicators for water pollution because they're sensitive to the concentration of dissolved oxygen in water.
Non-living indicators are things like satellites which can measure the temperature of the sea surface, weather stations that measure atmospheric temperature, rain gauges to measure rainfall, and dissolved oxygen meters to measure concentration of dissolved oxygen in water.
Answer:
Homologous structures can be described as the structures which are similar to one another present in different organisms. These similarities depict that the organisms might have a common ancestor i the past. For example, the forelimb of man, birds, dogs.
Analogous structures can be described as structures in different organisms which perform the same function but might not have a common origin. For example, the wings of bats and birds.
The fastest bird is a roadrunner