Lead enters the atmosphere as a particulate pollutant. this is a problem because it select one:

a. is a precious metal, and it is being lost to the atmosphere

b. will cause the ozone hole to increase

c. causes central nervous system damage in humans

d. can become attached to radon

e. provides excess nutrients to waterways, resulting in eutrophication

Which of the following types of stars is most likely to end up as a supernova? in graph a, the curve peaks at 800 nm, in the red section of the visible light spectrum. in graph b, the curve peaks at 550 nm, in the green section of the visible light spectrum. in graph c, the curve peaks at 450 nm, in the blue section of the visible light spectrum. in graph d, the curve peaks at 300 nm, in the violet section of the visible light spectrum. a b c d

Which best describes a benefit of using dna technology in medicine? a) medicine can be produced in mass quantities. b) medicine can be distributed at a reduced cost. c) medicines have fewer side effects. d) medicines are resistant to antibiotics.

Which enzyme is responsible for “unzipping" the dna by breaking the hydrogen bonds between the nucleotides?