Why is a disease more damaging to cloned crops?

Essentially all plant species exhibit heritable genetic variation for resistance to a variety of plant diseases caused by fungi, bacteria, oomycetes or viruses. Disease losses in crop monocultures are already significant, and would be greater but for applications of disease-controlling agrichemicals.

the answer is: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall.

a chair, a bed, and a toothbrush

explanation: