A. All four are protist membranes
b. Two are from the engulfed photosynthetic bacterium; one is a protist membrane; the other is from the food vacuole produced by the protist originally containing the bacterium.
c. Four membranes evolved from the protist's cell membrane.
d. All four are bacterial membranes.
e. One is from the bacterium; one is from the protist; one is from the bacterial nuclear membrane; one is from a food vacuole.
The nucleus! hope this helps :)
<span> I think Sea otters are an iconic species, representing the beauty and diversity of marine life found along California’s coastline. They’re also considered a keystone species because of their critical importance to the health and stability of the nearshore marine ecosystem. They eat sea urchins and other invertebrates that graze on giant kelp. Without sea otters, these grazing animals can destroy kelp forests and consequently the wide diversity of animals that depend upon kelp habitat for survival. Additionally, kelp forests protect coastlines from storm surge and absorb vast amounts of harmful carbon dioxide from the atmosphere. Sea otters are also considered a sentinel species because their health reflects that of California’s coastal waters.</span>