During the relative refractory period the cell may depolarize if

a. the stimulus is much weaker than normal
b. the stimulus is much larger than normal
c. enough potassium ions enter the cell
d. the myelin sheath is thick enough

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

Chlorophyll is found in plant leaves and absorbs light from the sun to enable plants to perform photosynthesis. magnesium is an important component of chlorophyll. the concentration of magnesium ions is higher in the root-hair cells of plants than in the soil. which mechanism of ion uptake would best enable a plant to produce a steady supply of chlorophyll? osmosis diffusion passive transport active transport

Explain the significance of the increased cell specialization of the volvocine line