Vertebrates have a bilateral symmetry due to which their entire body is divided into right and left halves while the invertebrates either have radial symmetry or the bilateral symmetry. Therefore, option D is correct.
The other basic differences between the vertebrates and the invertebrates are that vertebrates have a spinal cord and a backbone while invertebrates lack them, vertebrates have well developed brain, lungs or gills in respiratory system and closed circulatory system.
The answer is
letter A.
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In the
evolutionary sense fitness refers to the measure of reproductive success of an
individual or of organisms in general. Those organisms that leave the largest
number of mature offspring are the fittest. Fitness can be achieved through survival
or mortality selection, mating success or sexual selection, and family size or
fecundity selection. Fitness is critical for a species’ survival and is a major
adaptation that all organisms do through a long period of time. <span> </span></span>
Answer:
See
Explanation:
Given:
Brown allele (B) is dominant over the white allele (b).
It will be assumed that the alleles are not related to the X and Y chromosomes.
See attached diagram for details of the general case (for both homo-zygous and hetero-zygous parents)
For both parents hetero-zygous,
P1:
Genotype: Bb (100%)
Phenotype: brown (100%)
F1:
Genotypes : BB, Bb, bB and bb in equal proportions, i.e.
BB (25%), Bb (50%), bb (25%)
Phenotypes: 75% brown (from BB and Bb), 25% white (from bb)
Answer:
Sheep and goats are important livestock species in developing countries. Of the world's 1,614million sheep and 475 million goats, 65% and 95%, respectively, are located in developing countries. Fifty-three percent of the total small-ruminant population in the developing countries is found in Asia, particularly in India and Pakistan, 33% in Africa, and 14% in Latin America (FAO, 1984).
Goats are hardy and well-adapted to harsh climates. Due to their grazing habits and physiological characteristics, they are able to browse on plants that would normally not be eaten by other livestock species. Thus, the presence of goats in mixed species grazing systems can lead to a more efficient use of the natural resource base and add flexibility to the management of livestock. This last characteristic is especially desirable in fragile environments.
Sheep and goats contribute to a broad range of production systems. The most common system throughout the developing countries involve either the extensive system with large herds and/or flocks grazing on arid and semi-arid rangelands or the intensive system with smaller herds and/or flocks kept in confinement, mostly in the humid tropics.
<span>Too little is known about pre-Archean time, from the origin of Earth to 3.8 billion years ago, to divide that period into units.</span>
