Membrane receptors are specialized proteins that take part in communication between the cell and the outside world. The membrane protein receptor can be subdivided into three parts or domains. The portion of the protein in the E zone is extracellular (outside of the cell). The P zone is the plasma membrane and the I zone is intracellular (inside of the cell). A glucagon hormone is a molecule that stimulates a reaction inside liver cells. Based on the diagram, where do you think a glucagon hormone most likely binds to send its signal to the cell?

the growth of the plants is affected by the heat of the light. what is the student doing?

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.

idk what happened..you tell