In mutualism organisms compete for resources organisms of the same species work together organisms of different species benefit from cooperation organisms of the same species compete against each other

What element breaks down into yttrium-90?

What does the cell nucleus do or, how does it function?

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.