Which of the following is an example of reproductive isolation?
a.)two populations of finches that cannot produce viable offspring
b.)two populations of finches that have different feather colors
c.)two populations of salamanders that live in different lakes
d.)two populations of salamanders that have different tail lengths

A.) two populations of finches that cannot produce viable offspring.

Reproductive isolation refers to the phenomena in which members of the same species (intraspecific) or of different species (interspecific) are incapable of interbreeding because of behavioral, physiological, biological and geographical barriers.These species cannot produce viable fertile offsprings.

According to the above information, two populations of finches that cannot produce viable offspring is the correct example of the reproductive isolation. This is because of the fact that the two populations of the finches may either belong to same species or different species but due to the barriers like behavior, physiology and morphology they are incapable of interbreeding and producing viable fertile offsprings.

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .

1. a host loses nutrients to a parasite

2. a parasite only benefits when the host is alive (cause if the host dies the parasite dies with it )

3. producers to consumers

4. the tapeworm is a parasite

5. they convert energy from the sun (photosynthesis)

6. sunflower-robin (i think im 80% sure)

7. producer

8. consumer

9. prey

10. fresh water snails ( cause the green algea is the producer and the snails are the primary consumers and the small fish consumer so is the big fish)