Why is it beneficial for squid to have a thin, internal shell versus an external shell made of calcium similar to those of the nautilus or clam?

The table below shows the number of foot bones in some horse fossils.horse fossil recordhorse fossil number of foot bonesp 19q 17r 24s 13ancient horses had more bones in their foot then present-day horses. the present-day horse has 11 foot bones. what is the correct order of evolution of the horse starting from the youngest fossil? a. q p r s b. s r p q c. s q p r d. r p q s

What processes take place before the mature mrna exits the nucleus?

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.