Answer:
What are so called breast-cancer genes, are mutations in two genes: BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two), and are also associated with ovaric cancer. According to the question, these genes are present in the popolation despite surgeries and deaths, and asks why. Surgeries does not eliminate the genes, they eliminate the tumors, and people can still reproduce after that. And also, most people already had offspring before they know they have cancer, so they are inheriting the mutations on the genes anyway.
Explanation:
Answer:
because people where not alive yet oontill cenoznic era
Explanation:
A habitat is useful to animal because it is a place where they can easily adapt or wouldn't have to adapt. They could have as many right to food as they need, and they could easily find shelter.
Answer:
Option C - The sympatric salamander populations evolved their present body sizes after they became sympatric.
Explanation:
First, note the definitions of each terms.
1) Sympatric occurs when organisms especially of same species occurring in the same, or in overlapping territory, do not interbreed.
2) Allopatric occurs when organisms are NOT living in the same territory and thus unable to crossbreed.
On 1st QUESTION
The argument would be strengthened by the failure of P. cinereus and P. hoffmani to crossbreed making traits for body size to become distinct (dissimilar) in each specie.
On 2nd QUESTION
Definitely, salamanders species occurring in the territory, do not interbreed after they became sympatric, thus, making characters among same species to be increasingly different over generations.
The correct answer is (d) The number of plants and birds increases and the number of snail decreases.
Green plants are eaten by snails, snails by birds, and birds by household cat. If cat is removed from the cycle then the number of birds will increase which will decrease the number of snail in the environment. As there are large number of birds there will be a great demand of snails as a food for birds. Then there will be a decrease in the number of snails because of over eating of snails. There will be an increase in the number of garden plants because very less number of snails are left that will eat garden plants.
