Which statement correctly describes the muscular system of a flatworm
a. all of the muscles are attached to a center bone
b. it is made up of two layers of muscle
c. it is made up of three types of muscle tissue
d. all of the muscles are involuntary muscles

List two modern organisms that have pentameral symmetry

What is a gene ? a) a section of a protein that codes for dna. b) the alternate version of a trait. c) the visible trait in the f1 generation. d) a section of dna that codes for a specific trait .

What would be the result if crossing over did not happen during meiosis in humans? a. there would be less genetic variation in humans. b. parents would be more likely to look like their children. c. the human population could not reproduce. d. children would have more chromosomes.