If the inner lining of the air sacs is neither thin nor highly vascularized, then what can be inferred about the air sacs?
A) They must not belong to the respiratory system.
B) They cannot be derived from endoderm.
C) They are not efficient sites of gas exchange between air and blood.
D) They cannot effectively moisturize the air before it reaches the lungs.
C
You might also like to view...
Which layer of arteries and veins is made up of connective tissue and elastic fibers?
a. tunica intima b. tunica media c. tunica externa d. lumen
Turner syndrome (XO) is a sex chromosome aneuploidy. Of the effects listed below, which one is not usually seen in this syndrome?
A) unusually short stature B) infertility C) skeletal abnormalities D) unusually long limbs
Of what substance are intervertebral disks
made?
a. smooth muscle b. cartilage c. ligaments d. loose connective tissue e. epithelial tissue
What structure is responsible for selecting and transporting only properly processed eukaryotic mRNAs into the cytoplasm?
A. ribosomes B. spliceosome C. snRNPs D. nuclear pore complex E. RNA polymerase