The male
human has a sperm cell and the female has an egg cell. The cells from the male
and female that combine to form a zygote are called gametes. The human sperm
and egg cells each contain 23 chromosomes. . A combination of gametes forms a
zygote with 46 chromosomes. The type of cell division that produces gametes
with half the normal chromosome number is the meiosis. Meiosis is the type of
cell division used in sexual reproduction. It will occur in the testes and
ovaries.<span>Chromosomes get
shuffled when eggs and sperm are made. Though most adult cells contain two sets
of chromosomes, sperm and egg cells are different. These special cells have
just one chromosome from each pair. Which chromosome they get from each pair is
random, making each sperm or egg cell unique. There is also a bit of mixing
before the chromosomes are sorted into individual sperm or egg cells.
Chromosomes from each pair in a mother or father, respectively, make contact
and exchange pieces of DNA, creating hybrid chromosomes. </span>
Insertion
Genetic stability maintenance requires an extremely accurate mechanism for DNA replication and mechanisms for fixing the several accidental lesions that occur continually in DNA. Spontaneous changes in DNA are temporary due to immediate correction process called DNA repair. DNA repair’s importance is very evident from the huge investment that cells form in DNA repair enzymes. In 1000 accidental base changes in DNA , fewer than one results in a permanent mutation due to the efficient elimination by the DNA repair.<span> </span>
Plants get the carbon dioxide they need from the air through their leaves. It moves by diffusion through small holes in the underside of the leaf called stomata. These let carbon dioxide reach the other cells in the leaf, and also let the oxygen produced in photosynthesis leave the leaf easily.
Answer:
When the carbon dioxide concentrations rise, the air temperature will rise as well due to the greenhouse gases heating up and multiplying.
Explanation:
Carbon dioxide causes about 20 percent of Earth's greenhouse effect; water vapour accounts for about 50 percent; and clouds account for 25 percent. ... Likewise, when carbon dioxide concentrations rise, air temperatures go up, and more water vapour evaporates into the atmosphere—which then amplifies greenhouse heating.
