When the first antibiotics became available in the late 1940s and early 1950s, these antibiotics were effective against all bacterial infections. today however, there are a multitude of antibiotic resistant bacterial infections. what conclusion can be drawn? a) antibiotics of today are not as strong as those in the past. b) antibiotics cause dna mutations in bacteria, and over time, this has led to resistance. c) over time, bacteria have turned into viruses, and antibiotics have no affect over viruses. d) bacteria have become resistant to antibiotics over time due to evolution by means of natural selection.

1. seamount a raised footwall block between normal fault creates this 2. syncline break between rocks where a hanging wall rises relative to a footwall 3. hot spring on rolling hills, this a dip between hills 4. volcanic neck created when a block with hanging walls slips down between normal faults 5. caldera underwater volcano that never reaches above sea level 6. horst natural hot water on earth's surface containing many minerals 7. graben underwater volcano whose top is eroded flat by waves 8. crater less than a mile in diameter; looks like a bowl at the top of a volcano 9. guyot magma that filled the central vent that remains after the volcano has eroded 10. reverse fault over 1 mile in diameter; looks like a bowl over a volcano