Final answer:
The subject of this question is Health. Lifejackets are safety devices used to prevent drowning and are commonly used in water activities such as boating and swimming. The standard type lifejacket mentioned in the question refers to a keyhole-style flotation device that comes in two sizes.
Step-by-step explanation:
The subject of this question is Health. Lifejackets are safety devices used to prevent drowning and are commonly used in water activities such as boating and swimming. The standard type lifejacket mentioned in the question refers to a keyhole-style flotation device that comes in two sizes.