Answer:
False
Explanation:
Approximately 200 out of 200 million sperms ejaculated during intercourse reach the general vicinity of the egg. They sperms must undergo capacitation during which dilute inhibitory factors fluids of the female reproductive tract weaken the membrane of the sperm head so that head of the sperm can be broken easily when it came in contact with the egg.
The first sperm to reach an egg isn’t the one to fertilize it because the egg is surrounded by a gelatinous membrane called the zona pellucida. Outside this layer, a layer of small granulosa cells also present.
Therefore, it requires numerous sperm to clear a path through these barriers before one of them can penetrate the egg and fertilize it.
<span>Attached to each sugar ring is a </span>nucleotide base<span>, one of the four bases </span>Adenine<span> (A), </span>Guanine<span> (G), </span>Cytosine<span> (C), and </span>Thymine<span> (T). The first two (A, G) are examples of a </span>purine<span> which contains a six atom ring and five atom ring sharing two atoms. The second two (C, T) are examples of a </span>pyrimidine<span> which is composed of a single six atom ring. A </span>base pair<span> is one of the pairs A-T or C-G. Notice that each base pair consists of a purine and a pyrimidine. The nucleotides in a base pair are </span>complementary<span> which means their shape allows them to bond together with </span>hydrogen bonds<span>. The A-T pair forms two hydrogen bonds. The C-G pair forms three. The hydrogen bonding between complementary bases holds the two strands of DNA together. Hydrogen bonds are not chemical bonds. They can be easily disrupted. This permits the DNA strands to separate for </span>transcription<span> (copying DNA to RNA) and </span>replication<span> (copying DNA to DNA). In our simple model, the entire base pair structure is represented by the single blue rod. Various more elaborate models can be constructed to represent base pairs, including the one above which shows individual atoms and bonds.</span>
Natural selection :) In simple terms in the one with the best traits will repopulate so they can have the best traits the individuals who are weak typically die off and no one breeds with them :)
Both are extremely similar but have small changes that make all of the difference.
You've probably heard about how our bone structure is similar to many other animals', and likewise about our DNA.
When you observe these small changes, you will find organisms similar to each other where one little thing changes, and then another organism where there's <em>another</em> change, but that first change is also present. You can interpret evolution over different species just by looking at what's different in the bone structure as well as the genes and proteins.
The Ordovician is best known for its diverse marine invertebrates, including graptolites, trilobites, brachiopods, and the conodonts (early vertebrates). A typical marine community consisted of these animals, plus red and green algae, primitive fish, cephalopods, corals, crinoids, and gastropods.
