The answer is oxidation or chemical weathering. There are three main types of weathering, which includes, mechanical weathering, biological and chemical weathering. Mechanical weathering is caused by wind, sand rain, thawing, freezing, and other forces that can physically alter the rock. Biological weathering is caused by the activities of plants and animals as they grow, nests and burrow. Chemical weathering is caused by chemical reactions rather than by mechanical means.
The correct answer is A. Spontaneous generation does not happen.
He wanted to show that cells always come from other cells, meaning that cells and life organisms cannot come from non-matter or dead matter. Meaning that maggots in rotting bodies are not made from the bodies.
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20. The answer is 1 (Precambrian)
21. The answer is 4 (Pennsylvanian)
22. The answer is 2 (Bony Fishes, Dinosaurs, and Mammals)
23. The answer is 2 (Reptiles)
The correct answer is option A, that is, Phylum Porifera.
The species of Phylum Porifera are aquatic, that is, mostly marine. They exhibit cellular grade of the body, they are diploblastic animals with asymmetrical symmetry. They lack body cavity and exhibits a holozoic mode of nutrition with intracellular digestion.
They lack circulatory and nervous system and possess the tendency to regenerate their parts of the body. The organisms in phylum Porifera exhibits both asexual and sexual mode of reproduction.