the correct answer is A- Reproductive isolation occurred through behavioral isolation
A process of formation of a new species from an existing species is called speciation. New species may formed due to geographical or reproductive barriers which isolates the members of a population of a species to form a new species.
In the given question, speciation in In the leopard frogs occurred due to a particular or specific call given by males to the females. The courtship call lead to reproductive isolation due to change in behavior. Such type of behavioral change will help in recognizing mates of the same species and this will act as a reproductive barrier among the other related species.
Answer: A vascular bundle is a part of the transport system in vascular plants. A strand of conducting vessels in the stem or leaves of a plant, typically with phloem on the outside and xylem on the inside.
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Answer:
Option A, by having a constant supply of blood
Explanation:
Blood that flows to the muscles bring oxygen from the atmosphere to the contracting muscles where it gets consumed. During large muscle exercise, two physiological needs arise – a) high and prolonged muscle blood flow and b) regulation of blood pressure so that there is adequate perfusion of pressure to all organs. In order to meet both the requirements, the blood flow increases so that the vasoligating muscles do not outstrip the cardiac output.
Hence, option A is correct
Answer:
0
Explanation:
This question involves a single gene coding for wool color in sheeps. The allele for white wool (TT) is dominant over the allele for spotted wool (tt). This means that a sheep with an heterozygous genotype (Tt) will be white-wooled.
In this cross, 10 purebred white wool sheep (TT) are crossed with 10 spotted wool sheep (tt). This will give rise to all offsprings with heterozygous genotype: Tt (see attached image for punnet square). Since, white wool (T) is dominant, all the offsprings will have a white wool and none i.e. 0 will have a spotted wool.
Answer:
Self-antigens are not recognized and attacked by the T cells.
Explanation:
In immunology, the antigens are those substances which are bound by the antibodies. The antigens can be originated from within the bodies, known as self antigens or from outside the body, known as non-self antigens. The immune system identifies and attacks non-self invaders or the foreign harmful objects present in the body. It does not attack the self-antigens under the normal conditions. This is due to the negative selection of T cells of the thymus.
