80 chromosomes (40 pairs)
Microfilaments
Microfilaments are fine, thread-like protein fibers, 3-6 nm in diameter. They are composed predominantly of a contractile protein called actin, which is the most abundant cellular protein. Microfilaments' association with the protein myosin is responsible for muscle contraction. Microfilaments can also carry out cellular movements including gliding, contraction, and cytokinesis.
Microtubules
Microtubules are cylindrical tubes, 20-25 nm in diameter. They are composed of subunits of the protein tubulin--these subunits are termed alpha and beta. Microtubules act as a scaffold to determine cell shape, and provide a set of "tracks" for cell organelles and vesicles to move on. Microtubules also form the spindle fibers for separating chromosomes during mitosis. When arranged in geometric patterns inside flagella and cilia, they are used for locomotion.
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Answer:
Since the origin of humans on this planet, they have been trying their best to make their lives easier on this planet. In doing so, human activities have some how heavily damaged the Earth. Many day to day activities of humans are dangerous for the Earth.
Some of the consequences of human activities on the Earth's fresh water are :
Extinction of many aquatic species:
The water consumed by humans comes from the fresh water oceans. As the population of humans is increasing enormously, the water from the oceans is being consumed at dangerous levels. This has caused many species of aquatic animals to become extinct or to be at a verge of extinction as they do not have a habitat to survive or reproduce.
Pollution:
Many heavy industries, house sewage, farmers dispose waste into the fresh water. Hence, killing aquatic animals and polluting the fresh water ecosystems.
Explanation:
La principal diferencia entre la digestión mecánica y química es que la descomposición mecánica de partículas de alimentos grandes en partículas de alimentos pequeñas ocurre en la digestión mecánica, mientras que la descomposición química de compuestos con un alto peso molecular en compuestos con un bajo peso molecular
Answer:
Our bodies consist of a number of biological systems that carry out specific functions necessary for everyday living. The job of the circulatory system is to move blood, nutrients, oxygen, carbon dioxide, and hormones, around the body.
Explanation:
