Answer:
The law of superposition
Explanation:
The law of superposition is an axiom and a basic principle of sedimentary stratigraphy, it explains that the layers of sediment are deposited in a temporal sequence, in which the oldest are in a lower position than the most recent. Therefore, if there has been no deformation, the lower layers were deposited before the ones above, so they are older.
Answer:
C
Explanation:
Without crossing over, each chromosome would be either maternal or paternal, greatly reducing the number of possible genetic combinations, which would greatly reduce the amount of genetic variation between related individuals and within a species.
Descriptive studies are designed primarily to describe what is going on or what exists. Causal studies, which are also known as “experimental studies,” are designed to determine whether one or more variables causes or affects the value of other variables.
Reduces water loss compared to other nitrogenous wastes but requires more metabolic energy to produce
Mammals excretes urea as the primary nitrogenous waste product. On the other hand birds, and reptiles excretes uric acid as the primary nitrogenous product. They are called uricothelics because they can convert ammonia to uric acid. Uric acid is a compound similar to purines. This is produced through a complex metabolic pathway thay cost high energy. However it has advantages such as reducing water loss.