From the given choices, the first that would be deposited by the river is the sand. This is because sand are comparatively smaller than all of the given substances. This makes it easier for river to transport it and deposit it.
Correct answer - DNA and RNA.
Why? - Nucleic acids, macromolecules made out of units called nucleotides, come in two naturally occurring varieties: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
In ecology, a disturbance is a temporary change in environmental conditions that causes a pronounced change in an ecosystem.
Disturbances often act quickly and with great effect, to alter the physical structure or arrangement of biotic and abiotic elements.
Disturbance can also occur over a long period of time and can impact the biodiversity within an ecosystem.
Major ecological disturbances may include fires, flooding, storms, insect outbreaks and trampling.
Earthquakes, various types of volcanic eruptions, tsunami, firestorms, impact events, climate change, and the devastating effects of human impact on the environment (anthropogenic disturbances) such as clearcutting, forest clearing and the introduction of invasive species can be considered major disturbances.
Not only invasive species can have a profound effect on an ecosystem, but also naturally occurring species can cause disturbance by their behavior.
Disturbance forces can have profound immediate effects on ecosystems and can, accordingly, greatly alter the natural community. Because of these and the impacts on populations, disturbance determines the future shifts in dominance, various species successively becoming dominant as their life history characteristics, and associated life-forms, are exhibited over time.
They are homologous because they all evolved from the same structure
