Carbon monoxide detector goes off in middle of night

Ithink it’s a forms a perfect sphere or a smooth flattened oval

Ithink its solid. hope this

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .

The answer is d- principle of faunal succession.