Which of the following statements regarding the muscularis externa of the esophagus is true?
A) The upper third portion of the esophagus consists of smooth muscle, the middle third portion is a mixture of smooth and skeletal muscles, and the lower third consists of skeletal muscle.
B) The entire muscularis of the esophagus consists of skeletal muscle only.
C) The entire muscularis of the esophagus consists of smooth muscle only.
D) The upper third portion of the esophagus consists of smooth muscle, and the remaining portion is a mixture of skeletal and smooth muscles.
E) The upper third portion of the esophagus consists of skeletal muscle, the middle third portion is a mixture of skeletal and smooth muscles, and the lower third consists of smooth muscle.
E) The upper third portion of the esophagus consists of skeletal muscle, the middle third portion is a mixture of skeletal and smooth muscles, and the lower third consists of smooth muscle.
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Which statement about teeth is not correct?
A. Two sets of teeth develop during an individual's lifetime. B. There are four pairs of incisors, used for cutting and slicing. C. There are 32 permanent teeth. D. The premolars and molars have dental cusps for crushing and grinding. E. The canines are cone-shaped, and each has two roots.
Nets should be coarse and stiff in order to catch a fish more easily
Indicate whether the statement is true or false
The smallest type of white blood cell (only slightly larger than a red blood cell) is a
A. basophil. B. lymphocyte. C. monocyte. D. eosinophil. E. neutrophil.
True or False? Binocular vision gives one depth perception, which is the ability to distinguish between near and far objects.
Answer the following statement true (T) or false (F)