Dorsal rami

(a) unite to form plexuses in the cervical, brachial, lumbar, and sacral regions
(b) branch from spinal nerves to innervate muscles of the back
(c) contain cell bodies of sensory neurons
(d) are the structures to which the rami communicantes are attached
(e) are the structures that lead to the sympathetic trunk ganglia

the correct answer is the letter B)

Explanation:

the dorsal ramus of each spinal nerve travels backward, except for the first cervical, the fourth and fifth sacral, and the coccygeal. Dorsal rami divide into medial, intermediate, and lateral branches. The lateral branch supplies innervation to the iliocostalis muscle, as well as the skin lateral to the muscle on the back.

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation: