The common ancestor of sponges and other animals was probably
A) multicellular with tissues but without organ systems.
B) multicellular with tissues and many organ systems.
C) unicellular.
D) multicellular without tissues.
E) multicellular with tissues and a few organ systems.
D
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Most carbohydrates, lipids, and proteins are digested, and most nutrients and water are absorbed in the ________
a. small intestine b. stomach c. large intestine d. esophagus
Which of the following is an inorganic charged
particle found in soil?
a. humus b. clay c. sand d. silt e. all of these are charged inorganic soil particles
Molecules that form channels that allow selected molecules to cross the membrane are called
1.recognition proteins. 2.transport proteins. 3.receptor proteins. 4.glycoproteins. 5.cell adhesion proteins.
If ionizing radiation affects a germ cell then ____
a. no sperm or eggs will be made b. more eggs and sperm than normal will be produced c. sperm and eggs will contain the diploid number of chromosomes d. damage to the DNA will be inherited by an infant e. no problems will arise