Cope was hurt so he became an enemy toturned against Marsh. Cope was hurt so he turned against Marsh.

this cause and effect is a little wrong sounding

Cope told newspapers about all the bad things Marsh ever did. Cope told newspapers about all the bad things Marsh ever did.

all the...ever is a form to use again

Cope told newspapers about all the bad things Marsh ever did. Cope told newspapers about all the bad things Marsh ever did.

They had cheated on their work because they wanted to win. They had cheated on their work because they wanted to win.

win what? do you mean succeed? win requires a competition or competitive spirit.

So they blew up dig spotite when they are donefinished the research. So they blew up dig site when they finished the research.

dig-site is its own word I think

So they blew up the dig spot when they awere done with the research. So they blew up the dig spot when they were done with the research.

I wrote this after reading thean article. I wrote this after reading an article.

the requires the audience to know the topic

I wrote this after reading thean article. I wrote this after reading an article.

They studied of dinosaurs fossils together. They studied dinosaur fossils together.

They studied of dinosaurs fossil together. They studied dinosaurs fossil together.

But one day Code made a mistake when he was splicing dinosaur's code. But one day Code made a mistake when he was splicing dinosaur's code.

This sentence doesn't really make sense so I only fixed the grammar. I think you mean completely different words here, try using a machine translation here because "code" sounds like genes in this context.

But one day Code made a mistake when he was splicing dinosaurs code. But one day Code made a mistake when he was splicing dinosaur code.

He put the skull on the skeleton’s tail rather than the neck. He put the skull on the skeleton’s tail rather than the neck.

He put the skull on the skeleton’s tail rather than the neck. He put the skull on the skeleton’s tail rather than the neck.

And, Marsh made fun of this mistake. And, Marsh made fun of this mistake.

starting a sentence with And we use a comma. That said, I would have written something like "So," rather than And here.

And Marsh made fun of this mistake. Marsh made fun of this mistake.

All the things they did waThey did many things because of that disagreement. They did many things because of that disagreement.

This sentence feels isolated from the above

Both of them died in the late 1890s, without having made up. Both of them died in the late 1890s, without having made up.

I think you might want to resolve this so I added an example that's not a correction per se. This end feels very abrupt.