Answer:
c. Directional selection
Explanation:
Directional selection is a type of natural selection that occurs when selective pressure favors one extreme phenotype over any other phenotype existing in a population. Only one extreme phenotype is favored over time.
A good example of directional selection is the natural selection that occurs in giraffes, where alleles for long necks were favored against alleles for short necks as a result of selection pressure among the different phenotypes. Over time, giraffes having long necks dominated the population as the distribution of length of neck shifts towards the phenotype for long necks.
Answer: Meselson & Stahl reasoned that these experiments showed that DNA replication was semi-conservative: the DNA strands separate and each makes a copy of itself, so that each daughter molecule comprises one "old" and one "new" strand. The semi-conservative model, in which each strand of DNA serves as a template to make a new, complementary strand, seemed most likely based on DNA's structure. ... From the patterns of DNA labeling they saw, Meselson and Stahl confirmed that DNA is replicated semi-conservatively.
Explanation:
Un metal sólido no flota sobre su correspondiente fundido poque es mas denso que el mismo.
Que una sustancia flote en otra depende de sus densidades. La densidad es el cociente entre la masa y el volumen de un objeto. Los objetos menos denso flotan en los mas densos.
En general, los sólidos son mas densos que los líquidos, y estos que los gases. Esto se debe a las fuerzas de atracción que hacen que la misma masa ocupe menos volumen en el caso de los sólidos. Este es el caso de los metales sólidos que no flotan en su correspondiente fundido.
El hielo flotando sobre el agua es una excepción a esta regla general. El puente de hidrógeno en el agua hace que este tenga mas volumen que el liquido y por lo tanto sea menos denso.
Un metal sólido no flota sobre su correspondiente fundido poque es mas denso que el mismo.
Aprende mas: brainly.com/question/3944963
Answer:
The correct answer is They are very common in symbiosis in all plant families.
Explanation:
Nitrigen fixation is a process in which the atmospheric nitrogen is converted to ammonia by the help of nitrogen fixing bacteria such as azobacter, clostridium.
These bacteria lives in the root nodules of leguminous plants and some of them are free living soil bacteria such as azobacter.
These bacteria only form symbiotic relationship with the root leguminous plants but not with other plant families.
Semiconservative replication would produce two copies that each contained one of the original strands and one new strand. Conservative replication would leave the two original template DNA strands together in a double helix and would produce a copy composed of two new strands containing all of the new DNA base pairs.
