what does the notation rr mean to geneticists?
a-heterozygous allelesb-homozygous allelesc-dominant allelesd-recessive alleles

R: dominant allele
r: recessive allele

Heterozygous: two different alleles
Homozygous: two of the same allele

Rr is therefore Heterozygous (A), because there is 1 dominant and 1 recessive allele --> two different alleles. Hope this helps! :)

Glucose, also called grape sugar, blood sugar or corn sugar, is among the simplest and one of the primary naturally occurring sugars. produced naturally by plants as the primary photosynthesis product, it is heavily used by living beings as a main energy source and is necessary for cellular respiration. chemically, it is a monosaccharide carbohydrate and serves as a building block for complex sugars like starch.