Calculate the area of quadrilateral abcd state the units of your answer.

What is the answer for the question

Panthers and leopards prey on deer in an ecosystem. for unknown reasons, the population of leopards increased drastically. what are the likely effects of this change on the species? 1. more food for panthers and more competition for leopards 2. less food and more competition for panthers 3. fewer deer and more competition for panthers 4. more food for deer and less competition for panthers and leopards 5. more food for leopards and less competition for panthers

How do you work out 21.3-8= show your working. plz