All waves have which four characteristics?
a. wavelength, frequency, amplitude, speed
b. wavelength, crests, amplitude, speed
c. crests, troughs, amplitude, speed

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

Plz ! ive been stuck on this forever

Plz ! for many generations farmers in north america have been choosing to cross corn plants with large ears of corn each year this results in the new generation of plants also growing large ears of corn. what is the technique called? a. selective breeding. b. natural selection. c. mitosis. d. asexual budding.