What’s the difference between a primary source and a secondary source? A primary source was written by someone who actually experienced the event.

The difference is about where the source appears—online or in print.

Primary sources are shorter than secondary sources. The difference is about how closely the source relates to your topic.

PLEASE HELP ME

"A primary source was written by someone who actually experienced the event."

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?

sex cells are usually half's then they find another half and make a fertilize egg