I’m not for sure but I believe it is A
D. A struggle for existence is apparent.
If a struggle for existence is apparent, natural selection occurs because all of the weak/unfit/unadapted ones die.
The right answer is Ribosomes
The ribosome is a complex composed of RNA and ribosomal proteins, associated with a membrane (in the granular endoplasmic reticulum) or free in the cytoplasm. Common to all cells (prokaryotes and eukaryotes), the ribosome (and especially its composition) varies according to the organisms, even if it is always composed of two distinct subunits.
The ribosome is a huge ribonucleoprotein complex that allows the translation of mRNAs into proteins.
First, a complete digestive system means that the digestive tract has a beginning or the oral end and the opposite end or the aboral end. This is found in more complex animals starting from roundworms (flatworms have an incomplete digestive tract). A closed circulatory system is found in animals more recent than mollusks. The presence of the coelom makes it more evolved than the flatworms.
Specifically, a small animal with a segmented body, short stiff appendages, and soft skin with the above characteristics point out to the phylum Annelida or annelids.
