The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle)
Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as _____. A) structural homologies
B) vestiges
C) homoplasies
D) the result of shared ancestry
C
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The sub-atomic particle with a positive charge is _____
A. a neutron B. an isotope C. an electron D. a proton E. an ion
What is the function of lignin in a plant cell?
a. area for gas exchange b. growth c. support d. water conservation
Which of the following acts enzymatically rather
than hormonally? a. cholecystokinin b. pepsin c. secretin d. gastrin e. leptin
Aspergillus is a mold that causes an allergic reaction when its spores are inhaled
Indicate whether the statement is true or false