Reproductive isolation is both a cause and a result of speciation. During the process by which one species becomes two, a very powerful form of reproductive isolation is geographic isolation. This is called speciation.

2. if scientists identify an animal with bilateral symmetry and no segmentation, which phylum can it definitely not belong to? a. roundworms b. annelids c. mollusks d. flatworms

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.

List five ways we are indebted to phytoplankton