Expression of the a and b antigens on red blood cells is influenced by the fut1 gene. this gene encodes fucosyl transferase, an enzyme that produce the h substance. which of the following statements about the h substance is incorrect?
(a) individuals that cannot produce the h substance appear to be type o even if they have functional a and/or ib alleles.
(b) individuals that fail to produce the h substance are said to have the bombay phenotype.
(c) individuals that are heterozygous for the fut1 gene cannot produce the h substance
(d) the h substance is a substrate for the enzymes produced by the n and β genes. these enzymes add the appropriate terminal sugar to the h substance producing the a and b antigens, respectively.

The correct answer is option C

Explanation:

Bombay phenotype refers to a rare genetic trait in which a person appears as blood group O even in presence of functional A, B, or AB alleles.

It is because of recessive mutation that occurs in other locus, that is, FUT1 gene. Normal gene produces H antigen or protein in the cell. This antigen is essential for the final expression of the ABO alleles.

If a person is homozygous recessive then he or she is not able to produce H antigen due to which the blood group appears as O.

However, if a person carries even a single functional copy of FUT1 gene, that is, heterozygous or homozygous then he or she can efficiently produce H antigen and then ABO alleles are expressed accordingly.

Thus, option C contains incorrect statement.

did you fail the test? xd

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.