The answer is true.
A placer deposit is a deposit of earth, sand, or gravel formed due to the differential settling of the denser, heavier components. The placer contains particles of valuable mineral and it is found usually in the bed of a river or lake.
The answer is hydrogen bonds
Karyotyping can be used to detect a variety of genetic disorders. For example, a woman who has premature ovarian failure may have a chromosomal defect that karyotyping can pinpoint. The test is also useful for identifying the Philadelphia chromosome. Hope this helps :)