For an enzyme kinetics experiment, a student prepared a reaction mixture by mixing 450 microliters of 0.75mM PNPP with 4.25ml of 0.2M Tris-HCl buffer. When he is ready to measure the absorbance, he added 0.3ml of Alkaline Phosphatase to the mixture and mixed thoroughly. What is the substrate concentration at the beginning of the reaction in mM

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.