A focus of environmental science not studied in ecology is the

The influence of human activities on the environment

Explanation:

Anthropogenic activities may have negative effects on the environment by declining its biodiversity and by reducing natural resources. Human activities affect the environment through the use of fossil fuels (greenhouse gases), by contributing to the pollution of extensive areas, by overpopulation, eutrophication, deforestation, etc. The most significant effects of anthropogenic activities include the loss of biodiversity, climate change (global warming), habitat fragmentation, environmental degradation (e.g., ocean acidification), the introduction of invasive species, species extinction, etc.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.