Question

why are photosynthesizers usually the beginning of many food chains?
they produce organic energy rich molecules from sunlight
they consume oxygen
they produce oxygen
they consume carbon dioxide
they require water
question 21 2 pts
21
which of the following best describes cellular respiration
energy is released by breaking the bonds in organic molecules
performed only by autotrophs
sugars are produced from sunlight and inorganic molecules
oxygen is produced as a by - product
performed only by heterotrophs

Explanation:

First Question (Why are photosynthesizers usually the beginning of many food chains?):

Photosynthesizers (like plants) perform photosynthesis, which converts sunlight into organic energy - rich molecules (glucose). Food chains start with producers (photosynthesizers) because they are the source of energy - rich molecules that other organisms (consumers) can use. Consuming oxygen, producing oxygen, consuming carbon dioxide, or requiring water are not the main reasons they start food chains. The key is producing organic energy - rich molecules from sunlight.

Cellular respiration is the process where cells break down organic molecules (like glucose) to release energy. Autotrophs and heterotrophs both perform cellular respiration (so options about being performed only by autotrophs or heterotrophs are wrong). Producing sugars from sunlight and inorganic molecules is photosynthesis, and producing oxygen as a by - product is also part of photosynthesis, not cellular respiration. The correct description is that energy is released by breaking the bonds in organic molecules.

Answer:

They produce organic energy rich molecules from sunlight

Question 21 (Which of the following best describes cellular respiration?):