Choose all of the following situations below that are examples of pre-zygotic barriers to reproduction. (choose all that apply) a. ecological isolation b. incompatibility of sperm and eggs (sperm cannot fertilize the egg) c. two species of ants are capable of breeding under laboratory conditions, but do not because one species is only found in association with white pines and the other ant species is only associated with willows, thus the two ant species never occur together in nature to breed d. lions and tigers produce hybrid offspring, but all hybrids are sterile e. behavioral isolation f. the embryo dies due to a lethal combination of genes

satellites are frequently used to make observations of the orbit on earth

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.

geologic time scale (for gradpoint) =)