Reproductive isolation must happen
Answer:
Explanation:
The independent variable determines the value that needs to be calculated or the decision that needs to be made from the observations of the experiment. Hence, experimental design decision would most likely produce invalid and unreliable results when having more than one independent variable.
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical chemical energy that can later be released to fuel the organisms activities.
The correct answer is B. Ordovician period
Explanation:
Plants are mainly multicellular organism that depends mainly on photosynthesis to obtain energy, this includes a wide variety of species such as grass, flowering plants, trees, shrubs, etc. Additionally, plants are considered as one f the two major divisions or kingdoms along with animals. In terms of history, it has been determined first land plants appear during the mid-Ordovician period around 470 million ago, although organisms that were the origin of land plants developed in water in previous periods, also by the Devonian period a wide variety of plants have emerged with features that are still part of plants nowadays. Therefore, plant life first appeared on land during the Ordovician period.