A trilobite. Trilobites became extinct about 250 million years ago while a ammonite became extinct around the same time as dinosaurs(65 million years ago). You wouldn't find a human skull or a dinosaur footprint
The Punnet Square is used to determine the genotype and phenotype
<h2>Cell Cycle
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Explanation:
Eukaryotes grow and divide by cell cycle.
The main parts of a cell cycle are an ordered series of events – Gap 1 or G1 phase, Synthesis or S phase, Gap 2 or G2 phase, and the mitosis or M phases.
Interphase period (G1, S, G2 phases) - cell grows by size, duplicates its content, replicates its DNA, and finally prepares for mitotic cell division
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Mitosis and cytokinesis - formation of two identical daughter cells
Cell cycle is regulated by regulatory or restrictive checkpoints in the cell cycle which are activated with detection of a defective DNA.
Proliferation of undesired or cells with defective DNA like in case of tumor cells is controlled by the action of suppressing agents like p53 and cyclins.
The tumor suppressor gene protein p53 prohibits division of tumor cells. Cyclins regulate cell cycle by activation of the enzyme cyclin-dependent kinase.
Answer:
all the muscles.
Explanation:
The muscular system is composed of all muscles in the body. The main function of the muscles is to produce movement in different parts, voluntary or involuntary, creating equilibrium. Muscles are made of myocytes. There are three types of muscles: smooth muscle, skeletal muscle, and myocardium.
- The smooth muscle is formed by fusiform cells, mononucleated, and no transversal striations. There is a protein contraction system, but not as organized as the one of the skeletal muscle.
Smooth-muscle can be found in organs, vessels, veins, and arteries. It provides sustained contractions, slow and rhythmical, but not voluntary.
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Skeletal muscle is the most abundant muscle in vertebrates, constituting the somatic musculature. It proportionates motion to extremities and digits and is responsible for the position and posture of the individual. It is also involved in eye movements, respiration, mastication, deglutition, and phonation. It moves the tongue, the superior esophagus, and the pharynx.
The skeletal muscle is innervated by axons of the motor neurons coming from the CNS. The contraction of the skeletal muscle is voluntary and fast.
Cells composing the striated muscle are significantly long and multinucleated. They arrange in bundles, where cells are parallel to each other.
- Myocardium tissue is more similar to the striated tissue than to the smooth one. However, there are some differences between them. Cardiac cells are cylindrical and smaller, with ramifications. Cardiac cells only have one nucleus, and occasionally there can be two. Actin and myosin filaments are arranged just as the skeletal ones, and the contraction of cardiac cells is molecularly very similar to the skeletal
Answer:
Massena, New York
Explanation:
Polaris is most popularly known as the North star. It is also famous by the name of "Pole Star". It is the closet to the north celestial pole. At present it is the northern pole star currently.
It is found in the constellation of Ursa Minor. It is the one of the brightest star seen in the night sky. It is considered the star of the second magnitude which is situated close to the heaven's north pole.
The altitude of the Pole star or the Polaris when an observer is at the Tropic of Cancer is measured at 23.5 degree. While if the observer sees the Pole star at its zenith, the observer is located at the North Pole. i.e. 90 degree.
And the spot from where the observer views the Polaris at 45 degree altitude is Massena, New York.
