wild firing
selective cutting
clear cutting
tunneling microscope
compound light microscope
electron microscope
Cells were first observed through a simple microscope, which is the first option, as Antonie van Leeuwenhoek, a Dutch scientist, used a simple microscope that he designed and built himself to observe and describe microscopic organisms.
The history of the microscope goes back several centuries, with various scientists and inventors contributing to its development. One of the most notable figures in the history of microscopy is Antonie van Leeuwenhoek, who is considered the father of microbiology. He was a Dutch tradesman and amateur scientist who lived in the 17th century, and he was the first person to observe and describe microscopic organisms. Leeuwenhoek's microscope was a simple microscope, which means that it had only one lens. The lens was a small, spherical bead of glass that was mounted on a metal plate.
Hence, cells were first observed through a simple microscope, which is the first option.
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Answer:
Simple microscope
Explanation:
b. exhaustion level.
c. sweat rate.
d. heart rate.
Heart rate is the most accurate of the metrics available for measuring the effectiveness of exercise. Therefore, the correct option is D.
Heart rate is a useful indicator of the circulatory response to physical activity and can give an indication of the degree of physical exertion. Heart rate increases during activity to meet the body's oxygen and energy needs. Cardiovascular workload increases with exercise-induced heart rate.
To achieve specific fitness goals, people can set their exercise intensity and monitor their heart rate to ensure they are working within their target heart rate zone. Improvement in heart rate, or the speed at which heart rate returns to normal after exercise, can potentially reveal information about cardiovascular fitness.
Therefore, the correct option is D.
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b. gravel on the bottom of the aquarium
c. plants growing from the gravel
d. fish swimming in the water
I am pretty sure that the answer is B! I just took the Test and it makes sense because abiotic means not living feature and gravel isn't a living feature! Hope this helps!
Answer:
There will be 23 chromosomes in a sperm cell, 23 chromosomes in an egg cell, and 46 chromosomes in a white blood cell
Explanation:
Human cells are diploid in number i.e they exists in two basic sets (2N =46, where N is 23). So, cells of human body such as blood cells like white blood cells have two basic sets of chromosomes i.e 46 chromosomes, since they are produced by mitosis.
On the other hand, cells of humans involved in sexual reproduction such as the gametes (sperm and egg) have only one set of chromosomes since they are produced by meiosis - so they are haploid (N =23).
Answer:
Sperm=23
Egg cell=23
White blood cell=46
Explanation:
During cell division Meiosis produce haploid number of gametic chromosome 23.
The somatic cell contains 46 chromosome i.e diploid chromosome number. During cell division in meiosis gametes cells contains haploid number-23 chromosome which is half of the somatic cell chromosome.
During conjugation, haploid chromosome is donated by each parent to give a diploid organism with 46 chromosome number.
White blood cell contains 46 chromosome because it doesn't undergo cell division it is a somatic cell.
Orbital period of mercury can be calculated using the third law of Kepler which states that period squared equals to distance cubed, that is, (T1/T2)^2 = (a1/a2)^3 Where T1 is the orbital period of mercury, T2 is the earth orbital period and is equal to 1 year, that is, 365.25 days. a1 is the mercury axis and is equal to 0.39AU while a2 is the earth axis and is equal to 1AU. T^2 = (0.39)^3 = 0.059319 Therefore, T1 = 88 days.