Red blood cells are responsible for the distribution of oxygen to other cells in the body.
Internal means its on the inside
external means its on the outside
so an internal regulator is when the proteins respond to events on the inside of a cell
and an external regulator is when the proteins respond to events outside the cell
In cells with a nucleus, as in eukaryotes, the cell cycle is also divided into three periods: interphase, the mitotic (M) phase, and cytokinesis. During interphase, the cell grows, accumulating nutrients needed for mitosis, preparing it for cell division and duplicating its DNA.
Answer:
New moon, first quarter, full moon, and last quarter.
Answer is Middle Paleozoic era.
Paleozoic era was in 542 Ma - 245 Ma and it has 6 periods as Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
360-280 Ma - forming of vascular plants with woody tissues, seeds and veins.
430 - 410 Ma - forming of jawed fishes and first amphibians.
420 Ma - forming of scorpions
360 Ma - forming of crustaceans.
