Final answer:
The whipstitch is the most appropriate stitch to use for closing the end of the SRU-16P minimum survival kit due to its durability and practicality for rough conditions.
Step-by-step explanation:
To securely close the end of the SRU-16P minimum survival kit, the most appropriate stitch to use would be the whipstitch. This type of stitch involves wrapping the thread over the edge of the fabric, which can provide a sturdy closure for the kit. The whipstitch is practical for joining two pieces of fabric together with a seam that must withstand rough conditions and is also relatively quick and easy to execute, making it an ideal choice for survival gear.
A running stitch might be quicker but would not provide the same durability, while a backstitch would create a stronger seam but is more time-consuming. The blanket stitch is often used for edging but is not the best for sealing closed a survival kit. Therefore, using a whipstitch ensures the contents remain secure within the SRU-16P kit through various conditions that one might encounter in a survival situation.