Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate. The parasympathetic nervous system (PNS) releases the hormone acetylcholine to slow the heart rate. Such factors as stress, caffeine, and excitement may temporarily accelerate your heart rate, while meditating or taking slow, deep breaths may help to slow your heart rate.
Answer: Which is the BEST explanation for the drastic decrease in the number of dolphins killed after 1975?
A Tuna fishing was banned in 1975.
B. Dolphins stopped swimming with tuna.
C. Economic and political pressures were brought against tuna fishermen.
D. Dolphin deaths and tuna catches were not considered important after 1975.
Explanation: Improvements in fishing gear and techniques discussed in Chapter 7, the mandatory observer program, and the kill quota were responsible for the dramatic decline in the number of dolphins killed by boats in the U.S. fleet.
Answer:
Option A, the code is triplet
Explanation:
Complete question
When scientists were attempting to determine the structure of the genetic code, Crick and coworkers found that when three base additions or three base deletions occurred in a single gene, the wild-type phenotype was sometimes restored. These data supported the hypothesis that ________.
A) the code is triplet
B) the code contains internal punctuation
C) AUG is the initiating triplet
D) the code is overlapping
E) there are three amino acids per base
Solution
The team of Francis Crick was the first one to determine the length of the codon in 1961 by using a T4 bacteriophage. Through an assay, they devised the properties of genetic code and introduced frame shift mutation. So during the initial stage of experiment, only one single frame shift was introduced with in the viral protein of E. coli bacteria thereby making the protein nonfunctional. They then introduced an additional frame shift to restore the protein structure so that its function could be restored. This experiment was successful and concluded with a finding that genetic code is based on multiple of three bases
The correct answer is option (B) continental drift.
Continental drift is a theory explaining the movement of the earth’s continents over the geological time scale, drifting across the ocean bed. It was proposed by Alfred Wegener in 1912. Similar plants and animal fossils found around the shores of the different continents suggests that these continents were once joined as a single super continent named Pangaea. This Pangaea broke up long ago and the continents moved to their current positions. The ancient fossils of the same species of plants and animals were found on rocks of the same age but on the continents that are now widely separated.
Answer:
Hypothesis
Explanation:
In the scientific method used by scientist, The Hypothesis has a tentative or proposed explanation that gives report of an observed or measured phenomena. The hypothesis is usually based on previous observations which fails to be explained by available scientific theories. It is the starting point for further investigation that can be tested through experimentation.
