The layers of rock may be relatively dated, from youngest to oldest

That's true. This is possible through relative dating.

Explanation:

Relative dating establishes the chronological sequence of events (which happened first and which happened later) or fits a particular rock or formation within a certain time interval (Eon, Era, Period, Epoch) of the geological time scale. However, it does not allow you to identify your true age, that is, it does not assign a date or numerical age in its broad sense. This allows for a greater understanding of our planet and is crucial in areas such as stratigraphy and paleontology.

thymine. in rna, thymine is replace by uracil

answer: accepted answer: aquatic animals use the oxygen dissolved in water to carry out respiration. since the amount of dissolved oxygen in water is low as compared to the amount of oxygen in the air, therefore the rate of breathing in aquatic animals is much faster than it is in terrestrial animals.

explanation: