Only 20 plant species, such as rice, corn, and barely, make up the main sources of food for the entire human population. what best describes the reason for maintaining the biodiversity of these plants species?

A.)to prevent famines
B.)to prevent pollution
C.)to preserve the beauty of nature
D.)to enhance the survival
please let ne know.​

What are scientists who study fossils called? ( a ) astronomers. ( b ) biologists. ( c ) geologists. ( d ) paleontologists.

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit

Need what is special about water as a compound? how does water regulate climate? what drives water evaporation?   why is the water vapor fresh water when it rises from the ocean? why might freshwater in the form of snow take longer to enter the water cycle again than liquid precipitation?   what is an aquifer? what role do people play in the water cycle? plz just answer as many as you can ! thx if you !