Fill in the blank

the cell membrane is selectively permeable, or , which means that only some molecules can pass through the membrane.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

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find out why you don't need to aim at such a syllable pattern in english. you may have thought that haiku was supposed to be 5-7-5, so what's up with the logo by the gravitational pull of celestial objects, can touch us in unexpected ways.