The ability to roll your tongue is a dominant trait and the alleles are symbolized by R and r. Four siblings are genetically tested, and it is found that the genetic ratio is 2:2:0.

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.

the answer is d p: cell, q: organ, r: organ system, s: tissue

your answer is going to be physical weathering