Answer:
A.
Explanation:
The arctic soil is so cold that the ground beneath the tundra surface remains frozen all year. This permanently frozen ground is called permafrost. Each summer, when the sun warms the tundra surface, the top few inches of soil thaw. This melted part is called the active layer.
All of the above are needed. Nucleotides are the basic building blocks of new DNA, ATP energy is needed because replication is an active process, and enzymes catalyze the reactions needed to carry it out (e.g. helicase to separate the strands to be replicated, DNA polymerase to build the new strands, and ligase to "glue" the fragments together).
B. a volcano that erupts in blasts of the pyroclastic matter. D. would be wrong because the shield volcano can have explosive eruptions but they are generally quiet
Answer:
The economic principle that helps ensure that scarce resources are allocated efficiently is "the profit motive."
Explanation:
In economics, the profit motive is the inspiration of organizations that function so as to exploit their profits. Conventional micro-economic concept suggests that the eventual goal of a commercial is to make money. Specified differently, the aim for a business's presence is to chance a profit. The profit motive is the craving to make money. In a free market (where people willingly swap money, goods and services, the profit motive agrees who grows what. In theory, the profit motive dispenses resources efficiently, but in practice there are some problems.