Answer:
Yellow is a dominant trait.
Step-by-step explanation:
There are dominant alleles and recessive ones. Say Y is a dominant allele and y is a recessive one. YY makes yellow, Yy makes yellow, and yy makes green. It takes just one dominant allele to make a phenotype (physical traits) express it. Look at the photo to help guide you. Using a punnet square you can find that both parents give a dominant allele and it only takes one.
Hope this helps