D. The cytoplasm slides and forms a pseudopodium in front to move the cell forwards.
Prokaryotic cells DO NOT have centrioles, cytoskeleton, cilia or vesicles but they DO contain a prokaryotic flagella.
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Answer:
There are many types of evidence which support the theory of evolution such as comparative anatomy, fossil records, phylogenetic relationship, embryology et cetera
Comparative anatomy includes homologous organs and analogous organs. They support divergent and convergent evolution respectively.
For example, the homologous structure of limb of humans, birds, bat, horse, whale et cetera show that they are made up of the same set of bones which are humerus, radius, ulna, carpals, metacarpals, and phalanges.
It shows divergent evolution and supports that these organisms have evolved from a common ancestor.
Embryological evidence: When early stages of embryological development of different organisms are compared, it is found that these stages are similar at different levels of development.
For example:
- The appearance of pharyngeal-arch (gill-like structures) in vertebrates during embryo development.
- Salamanders and terrestrial frogs pass through larval stages within an egg. They possess the features similar to aquatic larvae, however, when they hatched out the eggs being ready for life on land.
The process of turning off and on of genes is known as gene regulation.
Explanation:
When the gene is turned on, it instructs the cells to construct a particular protein. The proteins are the molecules that build your body with collagen, tendons, and bones or keratin in your hair.
The gene regulatory proteins allow the individual genes of an organism to be turned on or off . in different cell types there are different selections of gene regulatory proteins. The patterns of the gene expression gives each cell its unique characteristics.
Each cell produces or turns on only a fraction of its genes. the remaining genes are repressed or turned off. this process is known as gene regulation. The signals from the environment or from other cells activate proteins called transcription factors.
Answer:
Attached to each sugar is one of four bases--adenine (A), cytosine (C), guanine (G), or thymine (T). The two strands are held together by hydrogen bonds between the bases, with adenine forming a base pair with thymine, and cytosine forming a base pair with guanine.
Explanation:
