What are the two variables that are incorporated in the hertzsprung-russell diagram?

a. a star's luminosity (brightness) and its surface temperature
b. a star's age and its surface temperature
c. a star's age and its distance from earth
d. a star's luminosity (brightness) and its distance from earth

Explain why the plants cortex would serve as the best food source for animals

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.

3what is the range of the function shownin the graph? ucation solutionsnw novo-9-8-7 -6 -5 -4 -3 -2 -1123456789