An allele for a particular trait that is only expressed in the presence of a second copy of the same allele is called

The correct answer is recessive.

Explanation:

The alternate forms of similar genes are known as alleles. A version of a gene, which to get expressed in the phenotype need to be homozygous at the time of inheritance is termed as a recessive allele. This shows that for a specific trait, a recessive allele only demonstrates its expression when a similar copy of the same allele is present.  

There are two forms of alleles known, these are dominant alleles and recessive alleles. The prime difference between the two is that the expression of a dominant allele is always witnessed, that is, whether it is in the heterozygous state or homozygous state. On the other hand, the expression of a recessive allele is only witnessed when it is in a homozygous state.  

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.

silty loam

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