You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

The fossils of dinosaurs that lived millions of years ago can be found in  
 (A) the water of oceans. (B) the ice on ponds. (C) the trunks of trees. (D) rocks in the ground.
D

During a biochemical reaction, pyruvate (C3H4O3) is converted into carbon dioxide (CO2) and water (H2O). In what cellular organelle does this biochemical reaction occur?  
 (A) nucleus (B) cytoplasm (C) mitochondria (D) endoplasmic reticulum
C

To help it survive, an organism has a capsule, endospore, and pili. To which group does this organism belong?  
 (A) bacteria (B) mollusk (C) insect (D) reptile

A