In the cells of the human body, oxygen molecules are used directly in a process that

Describe some of the common health conditions associated with air pollution.

Astairway has 6 steps. is it a handrail required? a. a handrail is required b. a handrail is not required c. double handrails are required d. only nosing is required

Which of the following supports the argument that viruses are nonliving? a) they are not cellular.b) their dna does not encode proteins.c) they have rna rather than dna.d) they do not evolve.