With which amino acid would you replace a Val in a transmembrane domain to maintain the hydrophobic character of this domain

The tubes transporting minerals and water upward are called ?

Why do some dna fragments move farther than others during gel electrophoresis? a. because their shapes are different b. because they are different types of molecules c. because the samples are different colors d. because their masses are different

Why has two different alleles for the same trait?