Two parents are heterozygous for a gene that has a simple dominant-recessive pattern of inheritance. If they
have four offspring, how many of the offspring will have the recessive-recessive genotype.
ne vour answer here.

one offspring out of the four will have a recessive-recessive genotype.

Explanation: A cross between two parents who are heterozygous for a gene that has a simple dominant-recessive pattern of inheritance will produce four offsprings: one will be homozygous dominant, two will be heterozygous dominant while one will be homozygous recessive.

Homozygous dominant offspring has two dominant alleles, heterozygous dominant offspring has one dominant allele and one recessive allele while a homozygous recessive offspring has two recessive alleles.

For example, a cross between two parents that are heterozygous (Tt) for tall will produce one TT, two Tt and one tt. TT is homozygous dominant, Tt is heterozygous dominant and tt is homozygous recessive. An offspring with genotype tt has a two recessive alleles thus have a recessive-recessive genotype. Therefore the number of offsprings with recessive-recessive genotype is one.

See the attached punnet square for more information

name and explain one of the event that occurs during meiosis that increases the variation in offspring even more than simple reproduction?

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.