4. Why do people have to be careful when breeding purebred doqs?

While quality breeders do test prospective parent dogs for defective genes -- and avoid breeding them if there are defects -- the broad problem of defects continues to grow as current breeding practices narrow the gene pool ever further. If you insist on a purebred puppy, then by all means, you should have one

d. in sexual reproduction, offspring have more chromosomes than

either parent.

asexual reproduction results in offspring which are genetically the same as the parent organism (not counting a rare mutation). sexual reproduction produces a random mixture of the genetics derived from both parents

explanation:

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.