The earliest photosynthetic organisms arose about:a
3.8?4.6 billion years ago.
b. 3.1?3.5 billion years ago.
c. 1.3 billion years ago.
d. 630 million years ago.
e. 250 million years ago.
B
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A key difference between transforming plant cells and human cells is
A. genes to be expressed in human cells require a eukaryotic promoter, and genes to be expressed in plants don't. B. DNA cannot be introduced into human cells. C. Agrobacterium is commonly used as a tool to directly transform plant cells but not human cells. D. a vector is needed to introduce DNA into human cells and not plant cells.
A structure used in rapid escape or pursuit is
indicated by letter a. A. b. B. c. C. d. D. e. E.
Cells take in and get rid of substances in various ways. Which process requires the expenditure of energy?
A) passive transport B) diffusion C) active transport D) osmosis
Carbohydrates provide energy for the body. Why would carbohydrates from an apple be healthier than those from a slice of apple pie?
What will be an ideal response?