In an example of cell-to-cell communication involving the substance TSH from the Pituitary Gland, which is the order of communication? (A) Pituitary: TSH  ducts  Thyroid Gland cell marker proteins  cell  Thyroxin  blood (B) Pituitary: TSH blood  Thyroid Gland cell receptor proteins  cell  Thyroxin  body (C) Pituitary: Thyroxin  blood  Thyroid cell channel-forming protein  cell TSH  body (D) Pituitary: TSH  Thyroid cell carrier molecule  channel  cell  Thyroxin body

the correct answer is b

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.

here's your answer.

burning fossil fouls really decrease the carbon in the atmosphere so b

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.