sentences: a chromosomes of a human contains thousands of genes
docs: human_chromosome is chromosome. human_gene is mammals_genes. human_y_chromosome is human_chromosome. human_tgfb1_gene is human_gene. humans has genes chromosome_1 is human_chromosome. chromosome_17 is human_chromosome. chromosome_5 is human_chromosome. neurons has nucleus_contains_genes human_x_chromosome is human_chromosome.