Misc: What is the fear of dirt or contamination known as?

Questions

It can take as long as ---------- hours to hard-boil an ostrich egg.?

It is estimated that millions of trees are planted by forgetful---------- .?

It is physically impossible for ---------- to look up in the sky.?

It takes ---------- head of cattle to produce one pound of adrenaline.?

It takes 12,000 head of cattle to produce one pound of---------- .?