Natural selection acts directly
a) alleles.
b) genes.
c) phenotypes.
d) mutations.

in a fox population, the allele frequency of a gene for red fur changes from 20 percent to 30 percent. what can you say about that population of foxes?
a) the population is expanding.
b) the population is evolving.
c) the population is decreasing.
d) the population is not evolving.

sexual reproduction among members of a population results in..
a) different types of alleles in the gene pool.
b) changes in the allele frequencies in the gene pool.
c) no changes in the allele frequencies in the gene pool.
d) an absence of genetic variation in the population.

genetic recombination includes the independent movement of chromosomes during meiosis as well
a)mutations from radiation
b) changes in the allele frequencies
c) crossing-over
d) mutations from chemicals

1. Answer;

C. phenotypes  

Explanation; Natural selection refers to the process in which organisms with favorable traits are more likely to reproduce and thus they pass on these traits to the next generation and over time these organisms adapt to their environment. Natural selection acts on the phenotype of an organism, also known as the observable traits. Phenotype is a product of the genotype and partially by the environment. The phenotype by certain alleles helps organisms adapt and thus reproduce better than others. 2. Answer;

A.The population is evolving  

Explanation; Allele frequency refers to the number of times a given allele occurs on the genetic locus in a given population. Allele frequency describes the fraction of gene copies of a specific allele in a defined population.  Allele frequency shows the genetic diversity of species population. Changes in allele frequency occurs as a result of forces of evolution such as mutations, natural selection, gene flow and genetic drift. Therefore, an increase in the allele frequency for red fur gene of fox population shows that the fox population is evolving. 3. Answer;

c) No changes in the allele frequencies in the gene pool.

Sexual reproduction among members of a population results in no changes in the allele frequencies in the gene pool.

Explanation; Allele frequency is the number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene.  It shows the genetic diversity of species population. Changes in allele frequency occurs as a result of forces of evolution such as mutations, natural selection, gene flow and genetic drift. Sexual reproduction combines alleles from different parents to produce offspring with different genotypes than the parents. However, sexual reproduction among members of a population results in no changes in the allele frequencies in the gene pool. 4. Answer;

Crossing over  

Genetic recombination includes the independent movement of chromosomes during meiosis as well as crossing over.

Explanation; Genetic recombination occurs when molecules of DNA exchange pieces of their genetic material with each other.  Genetic recombination mostly occurs during sexual reproduction, during prophase I of meiosis, when homologous chromosomes line up in pairs and exchange segments of DNA. Crossing over is the exchange of segments of chromosomes between non-sister chromatids during meiosis. This process results in new combinations of genes in the gametes from each parent and thus contributing to genetic diversity among organisms.

Science27 of the most iconic, jaw-dropping photos of the earth and the moon from spacedave mosher  oct 1, 2018, 11: 13 am etnasa/flickrapollo 11 astronauts took this photo of earth on july 20, 1969.from the ground, earth looks like a boundless fertile plain that beckons to be explored and exploited.but astronauts would beg -  and even plead  - to differ."you realize that people often say, 'i hope to go to heaven when i die,'" jim lovell, an astronaut who flew on the apollo 8 and apollo 13 missions to the moon, previously  told business insider. "in reality, if you think about it, you go to heaven when you're born."lovell has seen first-hand that we live on a tiny rock hopelessly lost in the void. he's also quick to tell you it's the only one we've got - a  fragile spaceship  for more than 7 billion people: "you arrive on a planet that has the proper mass, has the gravity to contain water and an atmosphere, which are the very essentials for life. and you arrive on this planet that's orbiting a star just at the right distance - not too far to be too cold, or too close to be too hot - and just at the right distance to absorb that star's energy and then, with that energy, cause life to evolve here in the first place. in reality, you know, god has really given us a stage, just looking at where we were around the moon, a stage on which we perform. and how that play turns out is up to us, i guess."humanity has recorded photos of earth from hundreds, thousands, millions, and even billions of miles away, some of them taken by lovell himself.these images not only scientists study our dynamic world, but also understand how a habitable planet looks from afar, which aids the search for  more worlds. most importantly, however, the images underscore our peculiar existence on  a mote of cosmic dust.take a moment to ponder 27 of the most arresting images of earth that humankind has ever captured from space.a