Females have two copies of the X chromosome, while males have one X and one Y chromosome. The 22 autosomes are numbered by size. The other two chromosomes, X and Y, are the sex chromosomes. This picture of the human chromosomes lined up in pairs is called a karyotype.
Of the 23 pairs of chromosomes, the first 22 pairs are called "autosomes." The final pair is called the "sex chromosomes." Sex chromosomes determine an individual's sex: females have two X chromosomes (XX), and males have an X and a Y chromosome (XY).
Even though there are no choices given in this particular question, the principle of osmosis is very easy to understand.
When we talk about osmosis, we are referring to the movement of water from a low concentration to a higher concentration. This is different from diffusion, which talks specifically about the movement of <em>solutes</em> in the solution (from a higher concentration to a lower concentration.)
When an RBC is placed inside a <em>hypertonic </em>solution, the water inside the RBC will go out thereby shrinking the RBC.
Inside an <em>isotonic</em> solution, the RBC will remain the same because the concentrations are equal.
Inside a <em>hypotonic</em> solution, the RBC will lyse or explode because water will move from the solution going inside the RBC.
Answer:
In nature, populations are usually evolving. The grass in an open meadow, the wolves in a forest, and even the bacteria in a person's body are all natural populations. And all of these populations are likely to be evolving for at least some of their genes. Evolution is happening right here, right now!
To be clear, that doesn't mean these populations are marching towards some final state of perfection. All evolution means is that a population is changing in its genetic makeup over generations. And the changes may be subtle—for instance, in a wolf population, there might be a shift in the frequency of a gene variant for black rather than gray fur. Sometimes, this type of change is due to natural selection. Other times, it comes from migration of new organisms into the population, or from random events—the evolutionary "luck of the draw."
I hope this helps a little bit.
