Sponges are sessile animals that have specialized cells called amoebocytes and choanocytes.
Sponges (phylum Porifera) are one of the simpllest multicellular organisms (first to branch off the evolutionary tree from the common ancestor of all animals) that have bodies full of pores and channels allowing water to circulate through them. Sponges’ s structure consists of two thin layers of cells and mesohyl layer between them. They don’ t have real tissues or organ systems such as nervous, digestive or circulatory systems. Constant water flow through their openings and pores obtain food and oxygen and remove wastes.
It form the contraction and relaxation of muscle
The genetic variation between humans and orangutans is the greatest is the right option.
Explanation:
A phylogenetic tree is illustration which shows evolutionary relationship between different species. This concept is based on Darwin's descent with modification.
Human and orangutan are 97% similar in their DNA sequences.
The difference in DNA bases shows large genetic variations in both the species.
The species are organized on the basis of traits that are changed over time as compared to their ancestors as they evolve.
Less related species will have more differences in their DNA sequence.
The phylogenetic tree formed indicates that orangutan and human are less related to each other than other species.
From your first part of the question, Muscle cells are the cells that make up our muscles. They are specialized cells that have fibers in them that contract as you move. This contraction causes the cell to change shape. The main function of muscle cells is to allow for body movement. Almost every part of the body has a muscle cell. Muscle cells contain mitochondria, nucleus and cell membrane just like all other cells.
Well, for the second question, The myofibres cause skeletal and cardiac muscles to appear striated because they are cyndrical and long, extending across the entire surface of the muscle. There are two types of striated muscle: skeletal muscle and cardiac muscle.
