Explanation:
In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
In the remaining cases, the error occurs after fertilization, as the embryo grows.
Answer to question no. 1:
A forest is at its young stage when it’s hardly touched by human
or any external or harmful intervention, leaving it as natural as it is. That
means it is filled with healthy vegetation, saplings everywhere, mature trees, vines
and shrubs.
In this very rich forest environment, many species of animals
thrive. Most of them would be endangered
species of migratory songbirds, mammals like white-tailed deers or rare
insects.
Answer to question no. 2:
Crocodiles are able to adapt in most areas and can live for a long
period of time due to several factors:
1)
They are cold-blooded. A cold-blooded animal would have very slow
metabolism so they can live without food for many months. One big meal can keep them full for a long
time.
2)
They can survive both on
land and water.
3)
Just like mammals, the
crocodile’s heart has four chambers that allows them to control their body
temperature at a constant level. This is why they are able to adapt in many
places.
4)
Crocodiles have strong
senses which makes them good hunters / predators
a. Sense of sight: they can see
underwater and have night vision
b. Good sense of smell
c. Sensory buds in their jaws that
help them detect vibrations and movements
Answer: b) controlling the amount of air entering the combustion tube
The rate of a reaction when using a Bunsen burner is changed by modifying the temperature of the flame.
In this type of burner, the temperature of the flame is modified by controlling the amount of air available for the flame. More air allowed will result in a hotter flame. This is achieved by turning the collar around the air holes.
Answer: <u>Fungi
</u>
Explanation:
Organisms with the capacity to breathe anaerobically and aerobically are typically called obligate anaerobes. Obligate anaerobes are usually microorganisms- microscopic organisms.
Since the organism described is land-dwelling, chitinous and eukaryotic (containing a plasma membrane enveloped nucleus), they are most likely fungi. Chitin is a rigid, non-soluble carbohydrate utilized for structural purposes. Typically these organisms have strong, insoluble cell walls, are multi-cellular and can form filamentous networks of hyphae.
They create a tangled network of mycelia and may be:
- Septate, with walls between every cell or
- Aseptate without walls
Answer:
defines a species as any group of actually or potentially interbreeding species that produce viable offspring.
Explanation:
<em>Biological species refers to a group of genetically and physically compatible organisms. These organisms are capable of mating or interbreeding and the offspring that result from this mating, as a rule of thumb, must be valid or fertile.</em>
Hence, species do not only share similar genetic materials (in form of DNA), they must also be physically compatible to mate and the resulting offspring from the mating must be fertile.
