In illumina nest generation sequencing the nucleotides are identified by

Step 3 in NGS Workflow: Data Analysis

After sequencing, the instrument software identifies nucleotides (a process called base calling) and the predicted accuracy of those base calls. During data analysis, you can import your sequencing data into a standard analysis tool or set up your own pipeline.

Explanation:

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i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.