A cell culture is centrifuged. Which cellular organelle would be concentrated at the top of the centrifuged mixture?
A. Nuclei
B. ER
C. Mitochondria
D. Ribosomes
E. Membrane bound proteins
I put ribosomes but the answer is C. Can someone help??
And also: an organism that demonstrates radial symmetry and an exoskeleton would be classified into which phylum?
A. Arthropods
B. Cnidaria
C. Echinodermata
D. Mollusca
E. Porifera
I put cnidarians because they definitely have radial symmetry however they have endoskeletons. I thought echinoderms had an endoskeleton too? The answer is C.
Thanks!