The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.
Since the Pitx1 gene codes for a protein crucial im lower limns development, a mutation occurring near Pitx1 gene will affect refikjs around the lower limbs but not those far away from it.
<h3>What are mutations?</h3>
Mutations refers to alterations or error that occur which change the original sequence of nucleotides in a DNA molecule.
The Pitx1 gene is a gene that codes for a protein that involved in development of the lower limbs.
A mutation near but outside of the coding region of Pitx1 may cause a loss of pelvic fins without pleiotropic effects on the pituitary gland and jaw because the pelvic fins form part of the lower limbs whole the jaws and the pituitary gland are not found in the lower limbs.
Therefore, the mutation occurring near Pitx1 gene will affect regions around the lower limbs but not those far away from it.
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Proteins that affect the structure of dna bound to histones without altering histone chemical structure are called Non-histone protein.
The proteins that remain after the histones have been taken out are known as non-histone proteins. A large group of heterogeneous proteins referred to as non-histone proteins organise and compress the chromosome into higher order structures.
They play a crucial role in regulating processes such nuclear transport, steroid hormone activity, nucleosome remodelling, DNA replication, RNA synthesis and processing, and the transition between interphase and mitosis.
Scaffold proteins, DNA polymerase, Heterochromatin Protein 1, and Polycomb are examples of typical non-histone proteins. This classification area also includes a large number of other structural, regulatory, and motor proteins. Non-histone proteins can be acidic. Other than histones, many proteins have the ability to bind to DNA and change the shape of the chromatin by means of epigenetic processes.
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Answer: B. The stream will have fewer plants growing
Explanation:
