Plz asap. thx for you answers algebra 2 sorry

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

The best solution for preventing harm to people and pets from severe hurricanes involves determining and warning residents about what

Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.