Answer:
False
Explanation:
The papillary muscles of both right and left ventricles began to contract shortly before the other ventricular muscles (systole) so that they can take up the slack on the chordae tendineae as the full force of ventricular contractions sends blood against the atrioventricular (AV) valve flaps.
They prevent the backward flow of blood to atria from ventricles. So if they contract after the ventricle systole they would not be able to perform their job.
Passive transport is the movement of materials through the cell membrane without the use of energy.
In biological<span> taxonomy, </span>race<span> is an informal rank in the taxonomic hierarchy, below the level of subspecies. ... </span>Races <span>may be genetically distinct phenotypic populations of interbreeding individuals within the same species.
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Answer:
Variation traits and natural selection.
Explanation:
Darwin stated that all species of organisms arise and develop through natural selection and inheritance of variations
In natural selection, survival was for the fittest. In order for an organism to survive . It had to develop new traits to adapt to its environment .
The variation increases its ability to compete, survive and reproduce. Through reproduction the desires trait is passed down making the organism to be considered fit.
Answer:
Option 3, 20 or 22
Explanation:
A newly discovered species of dung beetle has 2n = 16 chromosomes. It mates with a closely related beetle species that has 2n = 12 chromosomes. How many chromosomes would there be in an allotriploid beetle produced from this cross?
- 40 or 44
- 20 or 22
- 20 or 22
- 36 or 48
- 40 or 44
Solution
An allotriploid is a species which contains three sets of chromosomes of different species .Crossing can result in triploid offspring with diploid gamete of one species and regular haploid gamete of other offspring
Case I - Resulting offspring (3n) = Gamete I (2n) + Gamete II (n)
OR
Case II - Resulting offspring (3n) = Gamete II (2n) + Gamete I (n)
Case I
Case II
Hence, option 3 is correct
