Old existing cells.......
Answer:
The correct answer would be "Myosin heads attach to sites on actin filaments".
The muscle cell or myofibril consists of two types of protein filaments namely; actin (thin filament) and myosin (thick filament).
The myosin heads attach to the binding sites on the actin filaments and pull it towards the M-line in order to produce contraction.
The hydrolysis of ATP provides energy for this contraction cycle.
It is in your text book .
Check in your text book
Frost is capable of damaging the flower buds and blooms of fruiting plants to the extent that the plants will not bear fruit.
Essential services, such as water purification, nutrient cycling, and plant pollination are all examples of earth's Ecosystem services.
The ecosystem is defined as the interaction between the biological communities with its physical environment. The services provided by the ecosystem are termed as ecosystem services. The ecosystem with the help of its different components performs water filtration, recycling of the nutrients, pollination, seed dispersal etc. These all services provided by the ecosystem comes under the category of ecosystem services.