Answer:
C. Beak size is an inherited trait in the finch population under study.
D. Birds that could eat larger, tougher seeds survived and reproduced during the drought.
E. Beak size varies among the birds in the finch population under study.
Explanation:
The presence of genetic variations among the individuals of a population is required for natural selection to be operative. Natural selection targets the beneficial genetic variations present in the population. Natural selection refers to the differential reproductive and survival success of organisms of a population due to some beneficial genetic traits. These organisms with beneficial genetic traits are able to survive and leave more progeny under prevailing conditions.
If the natural selection has occurred in the ground finch population for the beak size, the beak size should be a genetic trait since natural selection works on genetic traits only. The finch population should have variations with respect to the beak size. The finches having the larger beak size that enabled them to feed on larger, tougher seeds should have higher survival and reproductive fitness during the drought.
Under these conditions, natural selection would favor the finches with larger beak size and would eventually result in an increase in the average beak size of the future generations.
Answer:
D) Expressed in the stomach, but not in the cells of the small intestine
Explanation:
Answer:
a) into the ER
b) into the ER
c) into mitochondria
Explanation:
a) This signal is located at the N-terminus of the protein and acts before the internal signal is synthesized for import into the nucleus. When the protein enters the ER, the sequence of the import signal in the nucleus cannot work because the protein would be prevented from interacting with the cytosolic receptors.
b) The signal that is imported into the peroxisome cannot function once the protein was sequestered in the ER.
c) In order for the protein to be retained in the ER, the protein must first be imported into the ER. Without there being no signal for that import of the protein into the ER, that retention signal could not work.
Answer:
Chemical weathering
Explanation:
Caves are formed by the dissolution of limestone. Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves.
Chemical weathering involves the decomposition of rocks due to chemical reactions between minerals such as calcite with water and gases in the atmosphere (e.g. carbon dioxide and sulphur dioxide). The solution of soluble minerals is particularly important in limestone landscapes.
Solutional caves or karst caves are the most frequently occurring caves. Such caves form in rock that is soluble; most occur in limestone, but they can also form in other rocks including chalk, dolomite, marble, salt, and gypsum.
Essentially, water reacts with carbon-dioxide to form carbonic acid. It then seeps slowly through the roof of the cave, depositing calcium carbonate, which hardens and builds up over time to form a stalactite.
