In a double-slit experiment, electrons are fired at an opaque barrier having two small slits, and a screen beyond the barrier records where the electrons hit. After many electrons are fired, what is observed on the screen?

A. The pattern observed indicates that electrons struck only the areas of the screen directly across from the two slits.

B. The pattern observed indicates that electrons struck the screen directly across from the two slits and the center of the screen

C. The pattern observed indicates that electrons struck only the center of the screen.

D. The pattern observed indicates that electrons struck the screen in alternating bands across the screen.

D. The pattern observed indicates that electrons struck the screen in alternating bands across the screen.

Explanation:

The moving electrons will behave as wave due to wave - particle duality . These waves will overlap to show interference pattern on the screen . A pattern of alternate  dark and bright band which reflects the concentration of electrons at some places and absence of electrons at others are shown. They are akin to interference band made in case of young's double slit experiment.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.