Which has been observed in the study of embryology? A. Species whose embryos have similar traits rarely have a common ancestor.
B. Species whose embryos have similar traits always have similar body forms as adults.
C. All traits present in early embryos remain throughout development.
D. Some traits in certain embryos disappear as the embryo develops.

D. Some traits in certain embryos disappear as the embryo develops

Explanation:

I don't know how I would explain it, but I can list some of the things that disappear such as...  Gill slits, and tails. Hope this helped :D

lysosomes contain a variety of enzymes, enabling the cell to break down various biomolecules it engulfs, including peptides, nucleic acids, carbohydrates, and lipids (lysosomal lipase). the enzymes responsible for this hydrolysis require an acidic environment for optimal activity. hope i !

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.