Wo sea urchin proteins were named cyclin a and b because, during the embryonic cell cycle, they were periodically
a. activated and inactivated by phosphorylation and dephosphorylation.
b. synthesized and degraded.
c. ubiquitylated and nonubiquitylated.
d. bound and released by another protein.

Is their a picture that goes along with it? ?

The answer is atmosphere. there are four spheres of the earth: 1. geosphere (from greek word 'geo' = ground), 2. hydrosphere (from greek word 'hydro' = water), 3. biosphere (from greek word 'bio' = life), and 4. atmosphere (from greek word 'atmo' = air). a magnetosphere is a region of space around astronomical objects controlled by the magnetic field of that object. through the process of elimination, since lightning is present in the air, it can be found in the atmosphere.

It makes up an community