動物 and 植物: broad groups and observation scope
Read the group names for animals and plants without expanding a limited investigation to the whole.
The group called animals
動物, read どうぶつ, means animal. この本では動物を紹介しています。 says that the book introduces animals.
動物の名前を調べました。 means researching animal names. It does not establish direct observation in the field.
The group called plants
植物, read しょくぶつ, means plant. 教室で植物を育てています。 means growing plants in a classroom.
植物の葉を観察しました。 means observing a plant's leaves. Do not add roots or flowers to the observed parts.
Scope of an investigation
庭にいる動物と庭にある植物を記録しました。 means recording the animals and plants in a garden. The example uses いる for animals and ある for plants.
一部の植物だけ調べました。 says that only some plants were examined. It does not mean that every organism in the garden was studied.
Does 植物の葉を観察しました establish that the roots were observed too?
Show the answer and why
No. The sentence explicitly identifies only the leaves as observed.