The respiratory system is responsible for taking in oxygen and releasing carbon dioxide. When a person walks, he or she breathes at a fairly slow rate. However, when he or she starts running, the oxygen reguirement of the body increases, and the body is
signaled to increase the rate at which the person breathes, Which body system interacts with the respiratory system to signal that the
body's oxygen reguirement has changed?

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

He table below gives the atomic mass and relative abundance values for the three isotopes of element m. relative abundance (%) atomic mass (amu) 78.99 23.9850 10.00 24.9858 11.01 25.9826 what is the average atomic mass (in amu) of element m? 2.86 5.36 24.30 24.98

Achemist weighed out 101.g of silver. calculate the number of moles of silver she weighed out.