The first living organisms appeared on Earth approximately
(a) 4.6 billion years ago.
(b) 3.8 billion years ago.
(c) 1 billion years ago.
(d) 6400 years ago.
(b) 3.8 billion years ago.
You might also like to view...
The membrane that contacts the endometrium
of the uterus is the
a. amnion. b. allantois. c. chorion. d. yolk sac. e. umbilical cord
Sea cucumbers will __________ when environmental conditions deteriorate
a. eject their digestive tract, respiratory structures, and gonads. b. crawl to an area with more favorable conditions. c. form a resistant spore. d. float to the surface and then later drop to a more favorable location. e. crawl deep into the ocean mud on the bottom.
If you could monitor the activity from the photoreceptors of rods and cones in the retina during a dream, would you expect these cells to be producing electrical signals? Why?
A) Yes, because the rods and cones are reproducing images that are then sent to the brain. B) Yes, because our eyes move during sleep, and this stimulates the rods and cones. C) No, because rods and cones only convert light energy into electrical signals. D) No, because rods and cones never produce electrical signals.
Given penicillin's role in inhibiting synthesis of peptidoglycan it would therefore work best against a _____
a) gram-positive pathogen b) archaeal pathogen c) fungal pathogen d) protist pathogen e) penicillin would not work against any of these pathogens