In humans, the yolk sac is the
site of origin for blood cells and primordial germ cells. The human yolk sac is
a membrane located outside the embryo and it is connected by a tube through the
umbilical opening to the embryo's midgut. The yolk sac serves as an early site
for the formation of blood and in time, is incorporated into the primitive gut
of the embryo.
The answer is D! birds have to migrate for winter to find an abundance of food! they learned this over time making it a learned adaptation
Answer:
DNA → mRNA → tRNA → Protein
DNA → mRNA → tRNA → Protein
Explanation:
This is because during protein synthesis, DNA is use to make RNA in the process called transcription. The DNA double strand is unwind by an enzyme called RNA polymerase to produce mRNA in the nucleus. The trans is produced in the nucleolus by RNA polymerase 1 and the site then binds aminoacyl tRNAs which is assembled in the RIBOSOMES. The tRNA are then translated into protein.
Species selection. Species selection is the process by which intrinsic biological characteristics in organisms change depending on the type of environment they're interacting with. In this case, the subsequent generations of the fly lost the ability to fly because their environment didn't require them to use wings for survival, hence they stopped growing them and subsequently lost the ability to fly.
