Answer:
1. Brain imaging such as CT scans or MRI's can provide evidence of a brain tumor.
2. Brain tumors are hard to treat because of where they are. The brain is the most delicate organ we have. The nerves, veins, blood vessels and more can make treating the tumor very difficult. Brain surgeries can be so complicated when it comes to tumors because any wrong moves and someone can be impaired for life.
Explanation:
I am going off my general knowledge here. I am not entirely sure but I am trying my best to help. Please let me know if it was close or not.
Answer: a. natural selection can only act on existing variation
Explanation:
Natural selection is the process of differential survival and reproduction. It occurs when a beneficial trait it passed on from the parents to the offsprings in the population of the same species. A beneficial trait will not be passed to the offspring if the trait is non heritable. The trait will be passed on as a genetic component. For example, beak length the trait for beak length or genetic variation is already present in the population. It is selected on the basis of the natural selection and can be expressed in the new generation. The natural selection process acts on the individual but the results of the selection can be seen on the entire population.
Answer:
- One spermatogonium produces 4 spermatids FALSE. One primary spermatocyte produces 4 spermatids.
Explanation:
Germ cells are diploid reproductive cells in charge of gamete production. Germ cells divide by mitosis and meiosis. Through mitosis, they originate more sexual cells, but through meiosis, they produce gametes -sperm and egg cells-. This process is known as gametogenesis.
Gametes´destiny is to merge during fecundation, and a new diploid cell called zygote emerges through fertilization. The zygote is a complete cell and suffers successive mitosis to form the new organism.
Spermatogenesis is the process of production and maturation of sperm cells. Spermatogonia are the masculine diploid germ cells, carrying 46 chromosomes. These germ cells suffer mitosis to reproduce. Some of them stay as spermatogonia, and some others become primary spermatocytes, which are in charge of gamete production. Primary spermatocytes are also diploid cells, meaning that they still carry 46 chromosomes.
Each primary spermatocyte replicates its genetic material and then goes through meiosis I to produce two daughter haploid cells called secondary spermatocytes, each of them carrying 23 chromosomes. Each secondary spermatocyte will produce two other haploid daughter cells by meiosis II.
The total result from the two cellular divisions of each primary spermatocyte is four haploid daughter cells called spermatids.
During spermiogenesis, spermatids mature into spermatozoa or sperm cells. Each sperm cell characterizes by being composed of a head, midpiece, and tail.
- DNA replicates once, but cells divide twice TRUE
- The products are spermatozoa that each have a head, midpiece, and tail TRUE
- Spermatids containing 23 chromosomes (1n) are produced TRUE
- One spermatogonium produces 4 spermatids FALSE. One primary spermatocyte produces 4 spermatids.
- Genetically diverse spermatids are created TRUE
Huddling is the correct awnser
Im pretty sure the answer would be the endocrine system, the nervous system, and the respiratory system