Scientist are always learning new things. which of the following shows how scientist use observations to gain new understanding about the world? a. scientists have discovered new planets orbiting a star by detecting a wobble in the star's motions. b. scientists hope to learn more about how many stars are in space. c. scientists are familiar with some galaxies, but they do not know how many galaxies exist. d. scientist wonder if other plants can support life, and some scientist wonder if there are aliens.

A., Scientists have discovered new planets orbiting a star by detecting a wobble in the star's motions.

This is because the other questions are saying how scientists still have questions about certain things in space, while answer A is already a confirmed answer.

i believe it is 40–40–20%

explanation:

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: