The atmosphere protects living things from harmful rays that come from
water
soil
the Sun
heat

Neelaredoxin is a 15-kda protein that is a gene product common in anaerobic prokaryotes. it has superoxide-scavenging activity, and it is constitutively expressed. in addition, its expression is not further induced during its exposure to o2 or h2o2 (silva, g., et al. 2001. j. bacteriol. 183: 4413–4420). which of the following statements best describes neelaredoxin synthesis? a-neelaredoxin is produced at all times; levels are constant even when exposed to o2 or h2o2.b-neelaredoxin is produced at all times; exposure to o2 or h2o2 increases expression. c-neelaredoxin is produced at all times; exposure to o2 or h2o2 decreases or prevents expression. d-neelaredoxin is only produced when there is exposure to o2 or h2o2.

In the diagram below, the northern hemisphere would be in what season at position a a. fall b. winter c. summer d. spring

Which structure in the cardiovascular system connect arteries to veins?