What has the greatest effect on the current decline of biodiversity?
a. plants
b. animals
c. humans
d. natural environment

Humans

Human activity has greatly distorted the ecosystems in the environment which resulted to invasive species.
Invasive species can threaten an ecosystem and the biodiversity of the organism that exist in the present environment when the invasive species increase rapidly in number. 
Exotic species are a threat to biodiversity because they alter the ecosystem of that area. They share food and habitat resulting in unbalanced ecosystem. Also, habitat destruction destroys the habitat of all the life forms in that area. 

This is what i found on google“ the monomers combine with each other via covalent bonds to form larger molecules known as polymers. in doing so, monomers release water molecules as byproducts. this type of reaction is known as dehydration synthesis, which means “to put together while losing water. in the process, a water molecule is formed.” i hope this you