Giving 20 points an earth-like planet is 500 light years away why is this an obstacle for a manned space mission a. there are no plans to send a human b. the cost is too low c. humans cannot live for 20 years d. the is no oxygen in space

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.