They probably got the new technology to discover these elements and also did more experiments
Evidence.
This are the two things explanations need: testability and evidence. Both of them are very important but evidence, I'd say, is the most important factor since it supports the claim in a remarcable way.
Hope it helped,
BioTeacher101
<u> False</u>
Deforestation is the process of loss or destruction of naturally occurring forests.
A for the first one and D for the second
In the reproductive system i believe