Why are amoebas more likely to use endocytosis than red algae?

Amoebas use pseudopods to surround their food and absorb it through their cell membranes into their vacuoles. This motion has its own name, "amoeboid movement", because amoebas don't have cilia or flagella to propel them, so they must extend their cytoplasm by stretching their cell membranes into the finger-like pseudopods which give them such a distinctive form of movement, and it is in this way that they surround their food and absorb it into their cytoplasm.
Red algae can perform photosynthesis, even though they look red to the eye. They still have chloroplasts and chlorophyll, but the red pigment present blocks our eyes from seeing the green chlorophyll, similar to Japanese maple trees, which have red leaves but which can perform phosynthesis just as well as other leaves.

Gravitational force i believe