Explain why life on land was difficult for early plants

What percentage of human sperm cells carry an X chromosome? a. 0% c. 50% b. 25% d. 100%

A tomato plant is mutated with gamma radiation. a cellular analysis reveals that atp synthase complexes found in the thylakoid membrane are inserted backwards into the membrane. what is the most likely outcome of this error?

Does rock minerals breaking apart and former small grains have to do with which one of the three main rock types

Before a scientific theory is accepted and supported, it has

What fraction of the earth is water

Which process describes nitrogen fixation?

As the fruit develops, why do the petals, stamen, and sepals fall off?

List at least 5 diseases/disorders that have been attributed to older "dumps ". ap environmental science

All the genes of all the members of a particular population make up the population's? Phenotype Species Genotype Gene Pool

If an animal has 42 chromosomes in its normal, non-gamete or somatic cells, what term would be given to the gametes that have 21 chromosomes