Scientists believe that green algae, chlorophyta, are the ancestors of land plants. volvox, a green algae, gives us a clue to this progression in plant form because, as seen here
a) single cells joined together to form a unique colonial body form.
b) volvox has an advanced body structure with cells, tissues, and organ systems.
c) single cells, that can no longer live independently, joined to form a colony.
d) volvox colonies are organized on the organ system level much life flowering plants.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.