Answer:
a. different alleles of the seed shape gene.
Explanation:
Mendel crossed different varieties of pea plants and he observed how phenotypic traits passed to the progeny. From these experiments, Mendel formulated the 'First Law of Segregation', where he observed that traits may exist in pairs that segregate (separate) at meiosis. During meiosis, i.e., gamete formation, these two factors separate from each other, thereby each gamete has the same probability of receiving either factor. Nowadays, we know that these two factors represent two different gene variants or 'alleles' for a given gene <em>locus</em>. Alleles can be classified into dominant or recessive as in the example above described, where the R factor (round) dominates on the r factor (wrinkled) to determine the seed shape.
Since all cells in our body contain DNA, there are lots of places for mutations to occur; however, some mutations cannot be passed on to offspring and do not matter for evolution. Somatic mutations<span> occur in non-reproductive cells and won't be passed onto offspring. For example, the golden color on half of this Red Delicious apple was caused by a somatic mutation. Its seeds will not carry the mutation.
</span>
A single germ line mutation can have a range of effects:
<span><span>No change occurs in phenotype.
Some mutations don't have any noticeable effect on the phenotype of an organism. This can happen in many situations: perhaps the mutation occurs in a stretch of DNA with no function, or perhaps the mutation occurs in a protein-coding region, but ends up not affecting the amino acid sequence of the protein.</span><span>Small change occurs in phenotype.
A single mutation caused this cat's ears to curl backwards slightly.</span><span>Big change occurs in phenotype.
Some really important phenotypic changes, like DDT resistance in insects are sometimes caused by single mutations. A single mutation can also have strong negative effects for the organism. Mutations that cause the death of an organism are called lethals — and it doesn't get more negative than that.</span></span>
Explanation:
I'm not an expert or sum, but with using logic I would choose: DNA plays a role in the growth and reproduction of organisms, DNA guides the formation of an organism's structures.
Answer:
Monospermy and Physiological Polyspermy. In general, the entry of more than two spermatozoa into the egg cytoplasm, referred to as polyspermy, causes aberrant effects on meiosis completion or embryo development and hence embryonic death, due mainly to excess male centrosomes delivered into the egg.
Explanation:
she need the essential for survival from other organisms to live
