Upon close inspection of movement in annelids and nematodes, you would notice an obvious difference. Nematodes tend to wriggle back and forth, while annelids tend to contract along their length as their girth swells and then thin out as they stretch. What anatomical feature explains this type of movement? Select one: a. The annelids possess longitudinal muscle fibers that the nematodes lack. b. The nematodes lack circular muscle fibers. c. Nematodes lack a coelom. d. Annelids have a highly specialized nervous system capable of more complex movements.

What anatomical feature explains this type of movement?

B.The nematodes lack circular muscle fibers.

Explanation:

Nematodes or roundworms are a an animal phylum inhabiting a broad range of environments, from the Animalia kingdom. They have adapted to almost every ecosystem. They are normally small. They lack circular muscle fibers. Instead, underneath the epidermis they have a layer of longitudinal muscle cells.

the answer is sex-linked recessive.

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.