Blimps were once filled with hydrogen, but now helium is used instead. Why is helium a better choice than hydrogen?
a Hydrogen is no longer available in pure form.
b Helium is cheaper than hydrogen.
C Hydrogen is flammable, while helium is not.
d Helium is lighter than hydrogen.

Are characterized by dry conditions, limited vegetation and wide temperature range. a.) tropical rain forests b.) deserts c.) grasslands d.) none of the above

4the indian leaf butterfly has traits that allow it to resemble a leaf. the bright colors of the monarch butterfly indicate that the butterfly tastes bad and can be poisonous. how does the appearance of these butterflies them to survive? f the indian leaf butterfly is able to avoid predators while the monarch butterfly warns predators away. g. the indian leaf butterfly frightens predators away while the monarch butterfly poisons predators before they can eat it. h both butterflies rely on camouflage to avoid predation. j both butterflies cooperate with one another to avoid predation.

Iwill mark brainliest and all that sha-bang. what is the function of the endocrine system? a. control longer term response in the body. b. transmit messages throughout the body. c. remove waste from the body. d. all of the above