In my opinion, I think any cengage 8th grade biology book is best. I believe cengage is the standard for US sciences. Hope this helps and happy learning!
1.
Marketing is one of the most important factors in determining the success of any fruit and vegetable farming enterprise. Marketing includes all the operations and decisions made by producers. These decisions range from deter-mining the most marketable crops for production to deciding how to best deliver quality produce to the consumers at a profit. However, contrary to popular belief, marketing does not begin after a crop is produced. Instead, marketing alternatives need to be considered even before production takes place.
2.
Recent environmental and food safety concerns in the United States produce sector have brought about increasing interest in organic fruit and vegetable production as an alternative to traditional fruit and vegetable enterprises. As a result, the production and marketing of organic crops has expanded steadily during the 1980s. However, as more organic producers enter the industry and it becomes more and more competitive, existing producers are forced to become better growers and more effective marketers.
Answer:
PVR is calculated by the formulae: 
Explanation:
Pulmonary vascular resistance may be defined as the resistance to blood through the pulmonary circulation.
PVR can be determined by the following formula:
Here, PAP is the pulmonary artery pressure, PAOP is pulmonary artery occlusion pressure and CO is cardiac output.
