Which cells have tiny holes through which nutrients move from cell to cell?
sieve tube
elements
tracheids
vessel elements

A sieve cell (or sieve tube) has narrow pores in which nutrients flow from cell to cell.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

i think the answer would d