A biologist puts a certain number of DNA strands into a machine, which uses a process called PCR cycling. Each PCR cycle, the machine creates a copy of every DNA strand. All of the DNA strands (the original DNA strands and their copies) remain together in the machine, ready for more PCR cycles. If a biologist puts $1$ thousand DNA strands into the machine and runs it for $4$ cycles, how many DNA strands will be in the machine at the end of the process, in thousands?

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Q. A biologist puts a certain number of DNA strands into a machine, which uses a process called PCR cycling. Each PCR cycle, the machine creates a copy of every DNA strand. All of the DNA strands (the original DNA strands and their copies) remain together in the machine, ready for more PCR cycles. If a biologist puts

1

thousand DNA strands into the machine and runs it for

4

cycles, how many DNA strands will be in the machine at the end of the process, in thousands?

PCR Cycling Process: Understand the process of PCR cycling. $\newline$ In PCR cycling, each DNA strand is duplicated, so the number of DNA strands doubles with each cycle.
First Cycle Calculation: Calculate the number of DNA strands after the first cycle. $\newline$ If we start with $1$ thousand DNA strands, after one cycle, we will have $1$ thousand $\times 2 = 2$ thousand DNA strands.
Second Cycle Calculation: Calculate the number of DNA strands after the second cycle. $\newline$ After the second cycle, the number of DNA strands will double again. So, $2 \, \text{thousand} \times 2 = 4 \, \text{thousand}$ DNA strands.
Third Cycle Calculation: Calculate the number of DNA strands after the third cycle. $\newline$ After the third cycle, the number of DNA strands will double once more. So, $4 \, \text{thousand} \times 2 = 8 \, \text{thousand}$ DNA strands.
Fourth Cycle Calculation: Calculate the number of DNA strands after the fourth cycle. $\newline$ After the fourth cycle, the number of DNA strands will double yet again. So, $8 \text{ thousand} \times 2 = 16 \text{ thousand}$ DNA strands.