When did photosynthesis begin? a about 1.2 billion years ago
b about 3 billion years ago
Cabout 4.6 billion years ago
d about 28 million years ago

20. in humans, freckles are dominant to no freckles. trey has no freckles and his wife anna grace has freckles, but her dad doesn't. they want to know what percentage of their kids would look like trey. show a punnett square to support your answer.

Climate like that in the sahara desert have the fastest rates of weathering

In the sentence "a mining company will consider the distribution of coal when deciding how to mine the coal," what does the word distribution mean?