Animal body plans Knowledge-Based Practice

Questions

1. 1.

   Which of the following morphological features is most directly associated with the evolution of bilateral symmetry in animal body plans?

   • A) Formation of only two primary embryonic germ layers
   • B) Organization of the nervous system as a diffuse nerve net
   • C) Cephalization with concentration of sensory structures at the anterior end
   • D) Division of the body into similar halves across multiple longitudinal planes
2. 2.

   Which of the following embryonic developmental patterns is characteristic of deuterostome animals?

   • A) Spiral cleavage, with the blastopore developing into the mouth
   • B) Determinate cleavage, with the coelom forming by splitting of solid mesodermal masses
   • C) Radial cleavage, with the blastopore developing into the anus
   • D) Direct development without gastrulation, with organs forming solely from ectoderm
3. 3.

   Which of the following characteristics distinguishes a coelomate animal from a pseudocoelomate animal?

   • A) The body cavity is completely lined by tissue derived from the mesoderm.
   • B) The body cavity forms directly between the mesoderm and the endoderm.
   • C) The digestive tract is formed without any specialized mesodermal tissue.
   • D) The organism develops from two embryonic germ layers instead of three.

Answers and step-by-step solutions appear after you finish the test.