Air pressure is caused by the .
A. local winds blowing
B. temperature of the air
C. Sun shining down on us
D. weight of the air above us

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

28. how many linkage groups will be formed by homogametic organism with 28 chromosomes?

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.