Tay-Sachs is a disease caused by malfunctioning lysosomes that do not digest cellular waste properly. Tay-Sachs occurs if a child inherits two recessive alleles for the Tay-Sachs gene. What is the probability that parents with the genotypes TT and Tt will have a child with Tay-Sachs?

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils