The answer is D. I’m an pretty sure it is D
Answer:
Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian
Explanation:
These all occurred in the paleozoic Era I hope you do great good luck <3
Answer:

Explanation:
Florine has the highest electronegativity and it thus pulls the element of
groups in the COOH group towards itself, making it relatively easy to loose the proton of the carboxyl group.
F O
↑ ||
F← C ← C ← O - H , Here three Florine withdraw
↓
F
F O
↑ ||
F← C ← C - O H , Here two Florine withdraw
↓
H
F O
| ||
H - C - C - OH , Here one Florine withdraw
↓
H
H O
| ||
H - C - C - OH , Here no Florine withdraw
|
H
I think the answer is 1. HF