In Mirabilis jalapa, all three shoot color phenotypes (pale, green, or variegated) are possible in progenies of variegated female parents regardless of the phenotype of the male parent to which it is crossed. This is because A. two kinds of plastids can be transmitted, and this is only through the female parent. B. the species have mutations in their nuclear genes which render inactivation of paternal chloroplast DNA. C. females exhibit overdominance, allowing for uniparental phenotype expression. D. nuclear genes of the female parent mask the expression of chloroplast genes.
Anatomy and Physiology of Special Sensory Organs
Sensory organs can be labeled as special sensory structures that permit sight, hearing, odor, and flavor. Sensory structures permitting proprioception, touch, thermal, and pain perception can be classified as more advanced sensory organs. The sensory neurons are trained to find out modifications in the external and internal conditions so that a person's body can react to that change. A stimulus is the first signal that is recognized by any sensory receptor of the body. Stimulus is an impulse generated when there is a change in the surroundings of a person. For example, a heated environment will alert the brain through the thermal sensory organs and generate a reflex accordingly.
Sensory Receptors
The human sensory system is one of the most complex and highly evolved structures, which processes a myriad of incoming messages. This well-coordinated system helps an organism or individual to respond to external stimuli, appropriately. The sensory receptors are an important part of the sensory system. These receptors are specialized epidermal cells that respond to external environmental stimuli. These receptors consist of structural and support cells that form the peripheral unit of the receptor and the neural dendrites which receive and detect the external stimuli.
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