Choose all the answers that apply. Chromosomes .

are tight coils of DNA
are carried on genes
always occur in pairs
can be analyzed in a karyotype
carry thousands of genes

carry thousands of genes

Explanation:

Genes are contained in chromosomes, which are in the cell nucleus. A chromosome contains hundreds to thousands of genes. Every normal human cell contains 23 pairs of chromosomes, for a total of 46 chromosomes. Some traits are caused by mutated genes that are inherited or that are the result of a new gene mutation.

tight coils of DNA

always occurs in pairs

carry thousand of genes

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.