Which scientific investigation does not include dependent and independent variable?
1.observing and counting bird populations
2.studying the effect of temperature on bacterial reproduction rates
3.investigating the effect of mass on the speed at which an object falls
4.testing a model car's air flow resistance at different wind speeds in a wind tunnel

the answer to you question is   jet streams

regents of the university of california v. bakke, 438 u.s. 265 (1978), was a landmark decision by the supreme court of the united states. it upheld affirmative action, allowing race to be one of several factors in college admission policy.

carbon atoms, hydrogen, oxygen, and nitrogen.

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.