Topsoil .
a) is devoid of charged particles
b) is a mixture of rock fragments, living organisms, and humus
c) is uniform in texture
d) is the relatively inert upper layer of soil
e) does not retain water

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.

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.