A base substitution of G:C to A:T after two rounds of replication.
First, preexisting rocks must weather/erode, forming the sediment that will eventually form the sedimentary rock. Then, that sediment must settle someplace, and over a long period of time, pressure begins to build. This causes the sediments to become compacted. After a long period of time (and a lot of pressure), the sediments cement together and form a sedimentary rock. In a nutshell, sedimentary rocks form through compaction, cementation, and eventually... lithification.
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Answer:
a) Maxillopoda is a diverse class of crustaceans including barnacles, copepods and a number of related animals. It does not appear to be a monophyletic group, and no single character unites all the members
b) General Characters of Hexapoda (Insects)
Ø A large taxa, includes insects and a small group of wingless arthropods.
Ø Body plan: 3 parts, head, thorax and abdomen.
Ø Head with six segments.
Ø Thorax with three pairs of jointed legs (hence the name hexapoda)
Ø Head bears a presegmental acron.
Ø Acron bears compound eyes.
