The red shifting of the nebula that Slipher observed was also referred to as what?

Slipher developed spectrographic methods that allowed researchers to see a Doppler effect in the distances of what were then called “spiral nebula,” what we today call galaxies. Simply put, by measuring the longer wavelength red shift (objects moving away) and shorter wavelength blue shift (objects moving closer), Slipher demonstrated that the universe was not static.

Explanation:

the best answer for these questions would be:

1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.