Which organism would be classified as an echinoderm?

Explain why biological control methods are generally environmentally superior to chemical pest control methods.

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere

What are antigens and antibodies? how are they involved in the body’s response to incompatible blood?