Match each description to the type of relationship it represents. 1. predator and prey
2. obligate parasitism
3. commensalism
4. facultative parasitism

-1- Rickettsia bacteria can only survive in eukaryotic cells, which are destroyed when the bacteria replicates.
-2- A freshwater amoeba feeds on bacteria in the water.
-3- A pseudoscorpion, a type of arthropod, hides under a beetle's wings for protection and transportation, but does not affect the beetle.
-4- Armillaria fungi grow within a tree's roots, causing the tree to rot, but will survive if the tree dies.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.