Your heart rate before exercising would probably be the at rest rate of say about 50-60 beats per minute whereas immediately after exercise it could easily be say 115-130 and depending on age there is an optimum heart rate for each age range which decreases somewhat with age. Timing for a full minute your heart rate is best as it will give the actual count whereas if you just do it for 10 seconds and then multply by 6 it would assume it will be consistent whereas it could decrease during the minute so the actual measured count for a full minute is more accurate.
Layer c is the oldest and then it’s b and a
Geiger-Muller tube is instruments requires you test three times the background of the work area.
<u>Explanation</u>:
These detectors are gas filled detectors and hence requires time for responding to the value. This time is taken because during this period it collects the electric charges and features of the electric circuit. It also gets stabilized during this period. This device has thumb rule i.e one must wait or hold for at the least 3 times the time constant before getting the precise and accurate reading. The time constant order is 10 seconds for the ionization chamber but for the Geiger counter it can vary from seconds to greater than 20 seconds
Answer: (B) Prothallus
Explanation: Prothallus is the gametophyte stage in the life of <u>a fern or other pteridophyte</u>.
The best description of predictable development of plant structure in an area over time is primary succession. The correct option is a.
<h3>What is succession?</h3>
Changes in the physical environment and the population of the species cause succession. There are two types of succession: primary and secondary succession.
Nudation, invasion, competition and coaction, reaction, and stabilization are the five stages of ecological succession. Autogenic succession is derived by biotic factor in an ecosystem.
Thus, the correct option is a. primary succession.
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