Answer:
Venous return (VR) is the flow of blood back to the heart.
Venous return to the right atrium is the most important factor determining cardiac output, provided both ventricles and the pulmonary circulation are normal.
Explanation:
Venous return refers to the flow of blood from the periphery back to the right atrium, and except for periods of a few seconds, it is equal to cardiac output.
Venous return is facilitated by a number of factors, including inspiration, increased total blood volume, increased venomotor tone, the cardiac suction effect, the presence of venous valves and the skeletal muscle pump.
Contraction of the skeletal muscles surrounding veins increases the pressure within the veins, pushing open the proximal valve and forcing blood toward the heart. For example, when calf muscles contract during exercise, blood is forced toward the heart, thus increasing venous return.
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Early diagnosis of childhood cancer is often difficult because the signs and symptoms are SIMILAR TO THOSE OF OTHER CHILDHOOD DISEASES.
Doctors generally find it difficult to diagnosis cancer i children because the accompany symptoms for the disease is quite similar to those of other diseases that children experience. Cancer in children usually occur very rapidly and its diagnosis in most cases typically occur at the late stage.
Answer:
D (3/4)
Explanation:
This cross involves a single gene coding for flower colour in pea plant where the purple allele (P) is dominant over the white allele (p) since the purple allele masks the expression of the white allele in a heterozygous state (Pp). A cross between two heterozygous plants (Pp) will produce four possible offsprings with genotypes PP, Pp and pp in the ratio 1:2:1.
The PP and Pp genotypes are purple flowered while the pp is white flowered. Hence, the probability of having purple flowered plants from this cross is 3 out of 4 i.e. 3/4.
The answer is 4 new (daughter) cells.
In meiosis, it produces 4 daughter cells which are genetically different from both the parent and the other daughter cells.
the parent cell first duplicates its chromosomes, just like mitosis (the kind of division that leads to 2 genetically identical daughter cells) . Then it divides, leading to 2 genetically identical daughter cells. But this does not end here. The 2 daughter cells further divides into total of 4 daughter cells, but without duplicating the DNA. That's why, the daughter cells has different DNA materials.
These daughter cells has half of the parents chromosomes, and we call them haploid.
Haploid cells are usually common in gametes. When an organism reproduces sexually, 2 gametes fuse together and leads to diversity.