Answer:
c. CNS
Explanation:
The Central Nervous System (CNS) is responsible for receiving and transmitting information throughout the body. We can define it with the command center that coordinates the activities of the body. It consists of the brain and spinal cord, which are protected by the skull and spine respectively.
Both structures are reinforced by three connective blades, called meninges. They are: dura mater, arachnoid and pia mater. Between the last two there is a fluid that is responsible for the nutrition of the CNS and the minimization of possible trauma caused by mechanical shocks.
The DNA is condensed before replication in the form of chromosomes and then the chromosomes are divided.
Answer: D. It yields chromosomes that contain both maternal and paternal DNA.
Explanation:
The recombination or crossing over is a genetic process. It takes place during the Prophase I of meiosis. The homologous pair align and held together by synapsis. This results in the mixture of genes combination formed from both parents that can be represented as a single chromosome.
If the recombination do not occur then each chromosome will be either 100% maternal or paternal. Thus recombination assures the recombinant chromosomes which consists of genetic material from both parents. Thus the genetic diversity of offspring increases.
Answer: C. Black snakes will not prey on cane toads in areas where cane toads have been present for 40–60 years.
Explanation:
Cane toad secret a toxin called bufotoxin which is a defense mechanism against predators. These defense mechanism is capable of killing black snakes if they eat cane toads. Within a period of 40 to 60 years, the black snakes in these area will be aware of the presence of a toxin capable of killing them in cane toads and will not prey on them. This phenomenon is termed learned behavioral adaptation.
