I believe it would be the bottleneck effect. hope that helps =)
You must've forgotten to put in the options for us to select from
They have limited access to nutrients. <span />
Answer:
1.It produces silk which is a high quality fibre
2.to destroy the gelatinious substance inside cocoon so as to obtain silk thread
3.To avoid it from hatching
4.they carry pollen grains while roaming plant to plant and help in cross pollination
