Schizocoelic development
The coelom is a fluid-filled body cavity, where the internal organs are suspended in. It is the cavity between the wall of the body and the digestive tract.
In the schizocoelic development of the embryo, the coelom, called the schizocoel, develops as a split in the mesoderm. The outer layer of the mesoderm attaches with the ectoderm to form a body's musculature, while the inner layer attaches with the endoderm to form the wall of the digestive tract.
This type of development is commonly found in annelids, arthropods, and mollusks.
Two or more organs form together make organ systems.
<u>Explanation:</u>
The basic unit of living organisms is the cell. Multiple cells makes up tissues and tissues make up organs. Two or more organs make up the organ system.
Human body has several organ systems. The organs that make up an organ system can be internal as well as external. Respiratory system is made up of organs like lungs, nose, pharynx, trachea, diaphragm etc. digestive system is made with organs like liver, small intestine, stomach, mouth , large intestine, pancreas etc.
increase because of carbon
All of the above are needed. Nucleotides are the basic building blocks of new DNA, ATP energy is needed because replication is an active process, and enzymes catalyze the reactions needed to carry it out (e.g. helicase to separate the strands to be replicated, DNA polymerase to build the new strands, and ligase to "glue" the fragments together).