Answer:
(d). B-cells.
Explanation:
Adaptive immunity can be described as immunity which develops in response to exposure to a pathogen (or foreign molecule). throughout the life. It is divided into two types, humoral immunity and cell-mediated immunity.
Humoral immunity is mediated by B cells that secrete antibodies against particular antigens. These antibodies recognize and neutralize the antigens and activate cell-mediated immunity, which is mediated by T cells.
Thus, the correct answer is option (d).
Scientists found that the first living things were likely prokaryotic because eukaryotic are evolved from the prokaryotic only.
<h3>What do you mean by Natural selection?</h3>
Natural selection may be defined as favorable variations that assist the organisms to survive and reproduce in a particular habitat.
Individuals that are better suited to their environment are likely to have more offspring and pass their genetic material on to future generations. This theory is referred to as Natural selection.
Scientists hypothesize that oxygen began to accumulate in the Earth's atmosphere after the appearance of living things with the ability to Photosynthesize.
To learn more about Photosynthesis, refer to the link:
brainly.com/question/19160081
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The answer is. Soils play an important role in all of our natural ecological cycles—carbon, nitrogen, oxygen, water and nutrient.A handful of soil can contain billions of different organisms that play a critical role in soil quality to support plant growth.
Answer:
As energy moves through trophic levels in an ecosystem the amount that is available decreases. ... A: Energy flows in a food web by being transferred to and between organisms as they undergo photosynthesis, are consumed by another organism, or decompose.