Make sure the knives or other utensils are sharp enough to cut your meat or vegetables. Make sure you keep hands away from the bottom edges of the utensils blades. Also, make sure you can focus both your hands and your fingers in order to prohibit cutting yourself from the blades. Keep your eyes on the item your cutting in order not to cut yourself.
Because semen swims upstream. The bladder is not located above the vagina (internally). If the ejaculation takes place in the vagina, the semen will swim up towards the cervix.
Pretty confident that it is A, judging by that the word composition is used as a combination or a ratio of 2 things. Also none of the other options make sense.
