What mechanism prevents or slows some chemicals from entering the brain, while allowing others to enter?

Antoine manages a number of apartment buildings that use natural gas for heating, cooking, and laundry. the scatter plot shows the correlation between the outside air temperature and antoine's natural gas bill. which type of correlation does the plot illustrate?

Black fur(b) in guinea pigs is dominant over white fur(b). find the probability of a homozygous offspring in a cross: bb x bb. a. 0% b. 25% c. 50% d. 75% e. 100%

First dropdown options: a. runoff b. condensation c. evaporation second dropdown options: a. photosynthesis b. transpiration c. sweating third dropdown options: a. raindrops b. clouds c. animals