I believe the first answer is #4 and the second is #1. Please correct me if I am wrong.
there is less energy on the 5th level, the less the energy, the smaller the food chain
LD50 or TD50: it is the Lethal Dose 50 (to refer to animals), and Toxic
Dose 50 (to refer to the human being). To refer to animals is: the dose of a
drug, a drug (generally a substance) that kills 50% of a population. To
refer to the human being: it is the dose of a drug, a medicine (in general a
substance) that produces toxicity to 50% of a population.<span>
<span>Find the LD50, it is very important to determine the
dose in which the drug produces toxic effects and thus be able to approach or
deduce the effective dose, that in cases of administering a new drug to the
human being, it is necessary to find the effective dose 50 (Dose of the drug
that produces a therapeutic effect to 50% of the population) in order to
determine the Therapeutic Margin or Therapeutic Index.</span></span>
