47. Steps involved in natural selection include: 1. Preservation of genes of best-adapted offspring 2. Overproduction of

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47.
Steps involved in natural selection include:
1. Preservation of genes of best-adapted offspring
2. Overproduction of offspring with variation in traits
3. Differential survival in the face of environmental
challenges
Which of the following is the sequence in which these steps take
place?
A. 3, 2, 1
B. 1, 3, 2
C. 2, 1, 3
D. 2, 3, 1
50.
Stem cells are valuable for medical research because they
A. Seek out and destroy disease-causing cells
B. Differentiate into types of cells that replace those lost to
disease
C. Correct abnormal expression of DNA in diseased cells
D. Replace malfunctioning cellular organelles
45.
Which of the following terms refers to the movement of air into
the lungs?
A. Perfusion
B. Ventilation
C. Gas Exchange
D. Tidal volume
46.
Which of the following is an appropriate description of the
arrangement of the cell membrane?
A. Fluid phospholipd bilayer containing embedded proteins
B. Rigid carbohydrate bilayer containing embedded
phospholipids
C. Rigid layer of phospholipids with proteins ont he outer
surface
D. Layers of protein and carbohydrates forming a fluid
structure