Answer:
The lungs
Explanation:
The lungs in your body get filled up with air when you inhale. There are blood vessels around the alveoli in your lungs (which are tiny air sacs that hold the air). The blood vessels absorb the oxygen in a process called diffusion where gas diffuses through the one cell thick wall of the alveoli into the blood vessels. The circulatory system then pumps the blood around your body to the cells that need the oxygen.
Answer:
The very first DNA isolation was done by a Swiss physician, Friedrich Miescher in 1869. He hoped to solve the fundamental principles of life, to determine the chemical composition of cells.
Explanation:
Crossing over, or genetic recombination contributes to genetic variation and diversity.
In early Prophase I of meiosis, crossing over occurs. This is the exchange of segments of chromosome, between non-sister homologous or similar chromatids crossing over happens at chiasmata, the point where non-sister chromosomes are joined. The chromosome pairs form tetrads held together at chiasmata.
Further Explanation:
All the genetic information within the eukaryotic cell is stored within the nucleus as helical DNA. This DNA is tightly wound around histones as chromosomes. To produce daughter cells, the chromosomes (total number of chromosomes (2n)) are copied before the cell splits into two daughter cells. This process is known as mitosis, and occurs in cell division and growth processes. Two new nuclei are formed, along with identical cells. These are the same as the parent cell and the chromosome number (2n) is maintained. Conversely in meiosis, the number of chromosomes (2n) is halved through meiotic divisions, producing 4 (n) germ cells (sperm or eggs), each containing half the number of chromosomes as its parent cell.
During the process of prophase I one the nuclear envelope containing chromosomes has only partly broken down homologous chromosomes are joined together by proteins and a complex or pairing call synapsis- corresponding genes on chromatids are aligned precisely. The syanpsis allows for crossing over which is the exchange of segments of chromosome, between non-sister homologous or similar chromatids crossing over happens at chiasmata, the point where non-sister chromosomes are joined.
Crossing over contributes to genetic variation and diversity; novel gene combinations in gametes are formed, which are not present in parent chromosomes. Genetic diversity describes all the genetic characteristics or traits within a species.
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Answer:
The answer is d because early forms of life were soft bodied
Explanation:
