Bronchoconstriction is treated by inhaled a. histamine antagonists b. opiates c. pentobarbitals d. cholinergic antagonists

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different

About how many years does it take for one cycle of surface water to become deep water and then surface water again in the oceans? 101001,000