Your skin is the largest organ of your body. the skin and its appendages, hair and nails, are known as the integumentary system. all but one of these are functions of your skin. a) aids in the production of vitamin d b) regulate your body temperature c) first line of protection against invaders d) semipermeable membrane to substances like glucose

D

Explanation:  

Your skin is not a semipermeable membrane to substances like glucose. Your cell membrane is the semipermeable structure that allows substance, such as glucose and water, to enter your cells.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

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- lead + phosphoric acid = hydrogen + lead(ii) phosphate