Gradual changes in the frequency of diseases over long periods are known as SECULAR TIME TRENDS. For example, the rate of mortality in USA due to coronary heart diseases over a period of time. Onset of puberty in girls is also a secular time trend.
Secular time trend is also referred as Secular Variation and Secular Drift.
Answer: It’s A or B I think
Explanation:
Because you will focus past ("overshoot") your specimen. (Like using a race car as a shopping cart: it's too fast, and you'll fly past the cereal and never even see it before you realize you need to stop.) Also: you risk crushing the slide and objective against each other (on older or cheaper scopes), and that would be a costly (and embarrassing) mistake.
You didn't give any answer choices (i'm answering this through research and what i already know)
the first is fossilized dung, and that's not generally gastropod shells. A carbon film would be something thin, seeing as it's a film, and gastropods aren't that. A gastrolith is a stone swallowed by an animal to help with digestion, and that's also not a gastropod.
<span>Gastropod fossils may be molds, but usually aren't. Still, they can be. It's a better answer than; film or stomach stones.</span>
As you move up to the food chain, the energy will decrease. This explains that the more the consumers, the lesser the energy that the last consumer will get from the sunlight. This is because each energy will decrease as it passes by the consumers because each consumers takes a portion of the full energy from the sun.
